Appendix A

329

Appendix A

Plant Care: Native Hawaiian Species

Common name: Aalii

Scientific name: Dodonaea viscosa

Origin: This species is native to all the

main Hawaiian Islands and occurs widely

throughout the tropics.

Special features: Aalii is a multi-branched

shrub or sometimes a small tree that can

grow to about 25 feet in height. It has red-

dish brown to blackish gray bark. The nar-

row leaves range from 1 to 4 inches long.

Although the leaves are variable, they are

often wavy, papery, and covered with a sticky covering. The small flow-

ers of aalii are greenish or yellowish to red. The dry fruits vary in color

from straw-colored to reddish purple. Each fruit has 2 to 4 papery wings

that contain a small, round seed.

Aalii is an extremely hardy plant that is resistant to wind, drought, and

salt spray. It is adapted to a variety of climates and habitats, occurring

from sea level to high elevations areas with a wide range of annual

rainfall. This plant prefers full to partial sun and well-drained soil,

although they can thrive in a variety of soils. The deep, fibrous root

system helps to stabilize the soil and prevent erosion. Once established,

it requires little maintenance.

Pruning: This plant responds well to pruning. Regular pruning can

promote uniform, thicker hedges. It can also be trimmed and shaped to

have a single trunk.

Irrigation: Aalii is drought tolerant and survives in dry conditions. Once

established, it requires minimal watering likely due to the extensive deep

root system.

Fertilization: Aalii needs little supplemental fertilization if the surround-

ing landscape is fertilized annually. Slow-release fertilizer every six

months. Over fertilizing can attract pests.

Common pests: This plant has relatively few insect pests, although

scales and mealy bugs have been observed, especially on new growth.

A systemic insecticide such as Orthene

or Merit

should control these

pests. Slugs have also been noted to consume aalii foliage at night.

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Common name: Alahee

Scientific name:

Psydrax odoratum

Origin: Alahee is indigenous to

all the main Hawaiian Islands.

It also occurs on the islands of

Micronesia and the South Pacific.

Special features: This shrub or

small tree has horizontal branch-

es and can grow between 20 and 30 feet tall. Its bark is durable and

whitish. The leaves are oval-shaped with pointed ends and about 2 to 3

inches long. The upper leaf surfaces are glossy, while the lower surfaces

are dull. The bright white flowers are arranged in clusters and can be

mildly to strongly fragrant. The Hawaiian name of this plant refers to

the flower’s fragrance (ala), which is slippery or elusive like an octopus

(hee). The roundish fruits are shiny green and turn blackish when ripe.

Many features of alahee resemble mock orange (Murraya spp.), an

introduced plant that is commonly used in landscaping.

This tough, drought tolerant plant can make an attractive hedge or

tree. Alahee can adapt to a variety of habitats from dry shrublands to

wet forests. It prefers full sun and well-drained soil, but tolerates partial

shade and moist conditions. Once established, alahee requires little

maintenance.

Pruning: In general, little to no pruning in necessary for this species. An-

nual maintenance pruning removes any dead or hazardous branches.

Irrigation: Alahee is drought tolerant. For a few months after outplant-

ing, supplemental irrigation may be necessary if plants show signs of

drought stress. Once established, minimal watering is required.

Fertilization: Young plants can be foliar feed with slow-release fertilizer

every six months. Once established, little supplemental fertilization is

necessary. If leaves appear yellowish, foliar feed them with Miracid

Common pests: Seeds are commonly attacked by seed borers. This

can be prevented by spraying developing fruits/seeds with a standard

insecticide. The species is also vulnerable to sucking insects like aphids,

scales, mealy bugs, and thrips. A systemic insecticide, such as Orthene

or Merit

, should control these pests.

Appendices

331

Common names:

Beach Naupaka,

Naupaka Kahakai

Scientific name: Scaevola sericea

Origin: This species of naupaka

is indigenous to the Hawaiian

Islands, as well as throughout the

tropical and subtropical Pacific

and Indian Ocean coasts.

Special features: Beach naupaka is a dense, spreading shrub that can

grow up to 10 feet tall and 6 to 15 feet wide. The waxy and fleshy

medium green leaves grow from 2 to 8 inches long. The flowers are

white or cream colored, often with purple streaks, and have a pleasant

fragrance. All five petals are on one side of the flower making them ap-

pear to have been torn in half. The fruits are fleshy white berries about

1/2 inch long. They can float for months in the ocean and still germi-

nate after having been in salt water for up to a year.

Naupaka is one of the most widely used of our native plants and can be

planted in practically every form of landscape, from beach parks, along

roads and highways, commercial lots, and anywhere else requiring low

maintenance and xeric needs. It is common in hot dry coastal areas on

most of the Hawaiian Islands. Naupaka is easy to grow from seed and

to propagate from cuttings. Even large cuttings up to 3 feet long can be

rooted.

Naupaka is very commonly used for hedges in medians in the ROW,

where it is often planted in combination with St. Augustine grass and

shower trees or monkeypods. It grows best in full sun but will tolerate

medium shade. Heavier shade, such as it may get under mature shower

or monkeypod trees, will produces lankier growth.

Pruning: Plants prune well, growing back thickly at cut branches and

twigs. It is best to hedge them often to prevent them from becoming

overgrown. Monthly pruning will keep them within size restrictions and

shaped well. Infrequent over pruning results in a bald appearance that

looks bad and takes a long time to fill back out. Keep lower branches

pruned high enough to provide enough room to mow and trim under

the hedge. Do not allow grass or other weeds or ground cover to grow

up inside the hedge.

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Fertilization: Beach naupaka grows well in clay, sand, cinder or coral

soils as long as drainage is good. It is wind tolerant and is not injured

by salt spray. It does not require much extra fertilizer. An annual appli-

cation of slow-release nitrogen fertilizer in the medians or in the general

landscape around the naupaka is enough for good growth of naupaka.

Irrigation: Naupaka is drought tolerant and does not require any more

water than is regularly supplied to the median or general landscape. If

irrigation is not used, normal rainfall is usually adequate in most loca-

tions in Hawaii.

Common pests: These shrubs are prone to ants, as well as scale, spider

mites and other sucking insects.

If treatment becomes necessary a systemic insecticide, such as Orthene

or Merit

, will control the infestation. Merit

applied as a soil drench

around the root zone is very effective for long-term control.

Common names: Hibiscus, aloalo

Scientific names: Hibiscus spp.

Hibiscus arnottianus

Hibiscus brackenridgei

Hibiscus clayi

Hibiscus furcellatus

Hibiscus kokio

Hibiscus tiliaceus

Hibiscus waimeae

Origin: Two of the native Hawaiian hibiscus

species (Hibiscus furcellatus and Hibiscus

tiliaceus) are indigenous to the Hawaiian Islands. The remaining five

native species are endemic, or found only in the Hawaiian Islands.

Special features: Hawaiian hibiscus flowers are found on all the main

Hawaiian Islands, except Niihau and Kahoolawe. Most Hawaiian hibis-

cus shrubs grow to a height of 3 to 15 feet tall with a spreading diam-

eter of 8 to 15 feet. Young Hawaiian hibiscus plants have smooth tan

trunks; the trunks of older plants have a wrinkled appearance. Hawai-

ian hibiscus shrubs bear blooms almost every day, but the blossoms last

only for a day even when on the bush. Each native Hawaiian hibiscus is

unique as described below.

Appendices

333

Hibiscus arnottianus – This small shrub or tree can grow over 30 feet

in height. It has several Hawaiian names including kokio keokeo, hau

hele, kokio kea or pua aloalo. These names all refer to the species’

white flowers. This plant is only found on Oahu, but an endangered

subspecies is also found on Molokai.

Hibiscus brackenridgei – Mao hau hele is a tall shrub (up 33 feet) with

bright yellow flowers. This species is the official State flower of Hawaii

and is also listed as endangered because few individuals remain in the

wild. Its Hawaiian name refers to the green (mao) dye and its branching

habit that is similar to Hibiscus tiliaceus (hau). In addition, it appears to

move (hele) because after several years of growth, the shrub falls over

then re-roots and forms a new shrub next to where it originally fell.

Hibiscus clayi – This endangered species is a shrub or small tree with

bright red flowers. It is only found on in dry forests on the Island of

Kauai.

Hibiscus furcellatus – This pink-flowered hibiscus is an herb or small

shrub. In Hawaiian it is known as akiohala, akiahala, hau hele, and

hau hele wai. It is often found growing near water (wai), such as wet-

lands or taro patches. This is the only species that is indigenous rather

than endemic to the Hawaiian Islands.

Hibiscus kokio – Kokio or kokio ula is a shrub or small tree (10-23 feet)

with red to orange (or rarely yellow) flowers. This species is not officially

listed as threatened or endangered, but is considered rare in nature.

Hibiscus tiliaceus – Hau is common on all the main Hawaiian Islands,

especially coastal areas.

Hibiscus waimeae – Kokio keokeo or kokio kea (white hibiscus) is a

gray-barked tree, 20-33 feet tall, with white flowers that fade to pink in

the afternoon. This hibiscus is only found on Kauai.

Pruning: Almost all of the native hibiscus (except Hibiscus brackenridgei)

can be pruned any time during the year to shape future growth, invigo-

rate old plants, manage plant size and get rid of diseased and dead

wood. Prune by shearing back longest branches every 4 to 6 weeks

to maintain shape. Leave the shorter branches to produce flowers. It

is recommended that native hibiscus be pruned less than introduced

hibiscuses that are often used as hedges. Over pruning native hibiscus

can make them more susceptible to insects and disease. Unlike most

hibiscus, the yellow-flowered Hibiscus brackenridgei does not respond

well

to pruning and does not perform well as a hedge.

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When pruning native Hawaiian hibiscuses, use sharp, clean shears and

make a clean cut just above and angled down and away from an “eye”

or node. Cutting above outward pointing “eyes” will encourage growth

in that direction. Fresh growth comes below every cut. The new growth

resulting from pruning invigorates the plant and will provide a source

for many new blooms. Regular pruning is necessary to have a bushy

plant and to control its shape. About half an inch of wood should be left

between the cut and the leaf node on each branch. See Chapter 6 for

details about pruning.

Fertilization: Fertilize lightly and often. Hibiscus is a heavy feeder but

does not tolerate excessive applications of water soluble fertilizers. Use

fertilizers that include the micronutrients iron, manganese, copper and

boron. Slow-release fertilizers may have advantages over conventional

water soluble ones.

A dry fertilizer, such as a 10-10-10, is acceptable; however, a low

phosphate fertilizer, such as a 7-2-7, is preferred as this might help

produce the most impressive quality and quantity of blooms. The so-

called “bloom specials” with the 10-40-10 type of formula are generally

avoided; phosphorous can build up in the soil over time and cause a

general decline in the health of tropical hibiscus plants.

Over-use of high nitrogen fertilizers may encourage leaf growth rather

than flower production. Water soluble fertilizers are good for spraying

leaves (foliar feeding). High phosphorous water soluble fertilizers can be

used successfully when applied as a foliar feeding. Slightly acid soil (a

pH of 6 to 7) helps the plant absorb nutrients. Hard water and proximity

to things like concrete can move the pH in the wrong direction – toward

an alkaline pH. Yellowing of leaves may indicate that the plant is under

stress either because of too much or too little fertilization, disease or a

variety of other reasons.

Soil and light: Hibiscus is tolerant to many conditions, but grows best

in well-drained sandy soil with some organic content and slight acidity.

For best results, the plants should have direct sunlight at least six hours

a day. The drainage should be good so that water will not pool at the

base of the plant. This can be tested by filling water in the pit taken for

planting and observing how long it takes to drain out.

Irrigation: New plantings of hibiscus need to get regular watering until

the roots are well established. Moisture retention is important, and

organic compost soil amendments added at planting and mulching the

surface around the planting hole helps to retain moisture in a sandy soil.

Appendices

335

Established hibiscus plants should receive regular watering either from

rainfall or irrigation. Irrigation watering cycles of once every two to three

days with run times that deliver about one inch of water at each water-

ing is adequate. Make sure there is no long lasting standing water after

irrigation. Hibiscus arnottianus requires more soil moisture than most

of the other native hibiscus species, while Hibiscus brackenridgei can

survive several months without watering

Common pests: Insects, such as aphids, thrips, scale, whiteflies, Chi-

nese rose beetles, and mites can be persistent pests. For most insect

problems Orthene

, a systemic pesticide, is widely used. Products such

as Merit

, containing the systemic active ingredient imidacloprid are

excellent for controlling most insects. Merit

can be applied as a soil

drench, and is an effective treatment for erinium mites when applied af-

ter infected branches are pruned out. Certain types of oils, such as Ultra

Fine Oil

, is effective for whiteflies and scales. Many report good results

with neem products. Plant native hibiscus near a street light to prevent

damage from the Chinese rose beetle or use a systemic herbicide such,

as Orthene

Water plants thoroughly before using insecticides to lessen shock. It

is usually best to apply in the early morning or late afternoon when

temperatures are below 80°F. When applying, both the tops and under-

sides of the leaves should be sprayed. When used as a soil drench, soak

the soil out to 10 feet from the base of the plants. Of course, follow the

label directions. NEVER use liquid Malathion

on hibiscus; it will cause

severe damage to the leaves resulting in yellowing and leaf drop.

Common name: Kou

Scientific name:

Cordia subcordata

Origin: Although this species was

originally believed to be brought to

the Hawaiian Islands by Polynesian

voyagers, recent evidence finds

that kou was actually in the islands

before humans arrived. It is now

considered indigenous to Hawaii.

Special features: Kou is a small evergreen tree with a broad, dense

wide canopy that grows to about 25 feet in height. The canopy can

spread to a width of 25 to 30 feet. The trunk is usually less than 16

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336

inches in diameter with pale gray flaky or furrowed bark. The bole of

the tree is often crooked and shaped by the wind. Large orange flowers

are formed all year at the ends of branches and in leaf axils and last

only a few days. The light green leaves are oblong with blunt ends and

about six inches long. Kou trees with variegated green and white leaves

are also known. Kou fruits are woody, small round balls. Generally, kou

fruit all year long, but may be sporadic. The green fruits soon become

brown and then dry to a blackish color when ripe. Young and old fruits

are on the tree all year and constantly fall to the ground, which may

present a hazard if planted too close to driveways, streets or along side-

walks where they can a present a threat for slipping.

Kou is naturally found at elevations from sea level to 100 feet in areas

with 40 to 160 inches of annual rainfall. Kou will not grow at higher

altitudes. It prefers neutral to alkaline soils (pH of 6.1 to 7.4), with soil

textures ranging from sand, sandy clay and clay. Kou prefers full sun but

tolerates some shading. It has a shallow root system and can be dam-

aged by too much surface disturbance. Once established, it requires

little maintenance. However, new shoots are readily produced from the

extensive shallow roots, sometimes forming thickets, and can become

naturalized in low elevation, dry, coastal areas.

Pruning: Kou trees will often grow crooked and corrective pruning dur-

ing the early establishment period is necessary to keep a nice shape.

Annual maintenance pruning to remove dead or hazardous branches

and sucker growth from the roots is necessary for established trees.

Irrigation: Kou trees are moderately drought tolerant and can survive

short dry conditions. The extensive shallow root system does not require

deep watering; consistent light irrigation is sufficient where annual rain-

fall is above 25 inches. Kou leaf drop makes excellent mulch. Leaving

the leaves in place will save water and maintenance costs.

Fertilization: Kou can grow in saline soils and tolerate some salt spray,

but heavy spray can severely damage leaves. Once established, kou

needs little supplemental fertilization if the surrounding landscape is

fertilized annually. Kou is not suitable on acidic clay soils, particularly on

former sugarcane lands.

Common pests: The kou leaf worm (Ethmia nigroapicella), from a

moth, can defoliate and kill kou trees. The wood is very termite resistant.

Large trees can develop heartwood rot.

Appendices

337

Common name:

Kukui nut (candlenut)

Scientific name:

Aleurites moluccana

Special features: The kukui nut

tree (often called candlenut) was

designated the official State tree

of Hawaii in 1959 due to its

beauty and usefulness to An-

cient Hawaiians. It is a medium

to large-sized ornamental tree, up to 50 feet tall, with wide-spreading

branches. The leaves are variable in shape. Young leaves are large, up

to 12 inches long, palmate, with three to seven lobes. Mature leaves are

oval shaped with long petioles, whitish on top when young and green

with age. The dingy white or creamy flowers are not showy. The round

fruit is a nut 2 inches or more in diameter. The thick rough hard shell,

making up about 2/3 of the fruit, is difficult to separate from the kernels

and contains one or two seeds.

Kukui trees can be planted as a single tree or used as hedges. They

withstand both steady strong winds and severe storm winds, which

makes them suitable for windbreaks or soil stabilization. They thrive

in moist tropical regions up to 2,300 feet altitude. Kukui prefers well-

drained, medium textured soils with pH of 5.0 to 8.0. They do best in

full sun but tolerate up to 25% shade. Kukui is usually propagated from

seed, requiring three to four months to germinate. Once established,

trees require little to no attention, depending on their intended use.

This species is originally native to tropical Asia, but was first brought to

the Hawaiian Islands by Polynesian voyagers to be used for light, medi-

cine and dyes.

Pruning: Kukui trees and hedges can re-grow after very occasional

severe pruning, but tend to die out if severe pruning is too frequent.

Lower branches tend to remain on the trunk and should be periodically

removed during the first five to 10 years of establishment if the tree is

to be used as a single specimen. Because of the multiple stem growth

habit, the trunk of single trees tends to be very crooked and multi-

branched, even with corrective pruning.

Irrigation: Kukui is quite drought tolerant when established, but grows

best with regular irrigation. In the wild, kukui is an indicator of stream

courses. It tolerates moderate salt spray but not highly saline soils.

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Common name: Milo

Scientific name:

Thespesia populnea

Origin: This species is currently

considered indigenous to the Ha-

waiian Islands, but may have been

introduced to the islands by early

Polynesians.

Special features: Milo is a small tree or shrub that reaches a height of

20 to 35 feet and a trunk diameter of 8 to 12 inches. The leaves are

a glossy dark green and the canopy is round and dense. It produces

yellow hibiscus-like flowers throughout the year that last only one day

before drop. Seed pods and leaves are also dropped constantly and

make for a litter problem in maintained urban areas.

Milo grows at elevations from sea level to 900 feet in areas that receive

20 to 60 inches of annual rainfall. It prefers full sun and does not do

well as an understory shrub. It tolerates steady coastal winds and is

very tolerant of salt spray. It is a tough plant and can survive the poor

drainage and hot, dry conditions common to urban areas and rural

roadsides.

Pruning: Milo does not self prune well, tending to develop crooked

stems with stout, low branches that stay on the main structure of the

tree. It forms multiple trunks and must be pruned to a single-stem tree

form in the early stages of establishment. Mature trees are large and

gnarled, spreading out rather than growing tall. Milo tolerates heavy

pruning, even if topped, but this weakens the new growth and branches

will never be as strong as original branches. Prune mature trees only to

remove dead wood and for minor corrective pruning.

Fertilizer: Kukui trees grow in a variety of soils, including low fertility

soils. Regular fertilization during the first several years of establishment

is beneficial. If the general landscape is fertilized on an annual basis,

the kukui will need no further fertilization.

Common pests: A number of fungus diseases are known to attack

kukui trees. These are more common in wet locations where the ku-

kui remains un-pruned. Soil nematodes may also become a localized

problem.

Appendices

339

Irrigation: Milo develops a deep tap root in sandy soils once estab-

lished and can withstand long dry periods. When planted on shallow,

rocky or occasionally flooded soils, roots tend to be shallow, spreading

on the surface. Once established, milo should not require irrigation

other than from normal rainfall.

Fertilizer: Milo thrives on sandy coastal soils, tolerates saline soils, and

does not do well on upland acidic clay soils. A pH range of 6.0 to 7.4

is best. Fertilize annually with a balanced slow-release fertilizer for the

first five years of establishment. After the tree is established, additional

fertilization other than for the general surrounding landscape is not

necessary.

Common pests: Milo is highly resistant to drywood termites. It is sus-

ceptible to fungal leaf spot and to a fungal root and stem rot. These are

more common in wet, un-pruned growth.

Common name: Naio,

bastard sandalwood

Scientific name: Myoporum

sandwicense

Origin: Naio is native to all the

main Hawaiian Islands and also

occurs in the Cook Islands.

Special features: This plant has

a highly variable appearance, ranging from a prostrate, sprawling form

(“naio papa”) to an erect shrub or small tree up to 15 feet tall. The bark

is dark yellow-green and can smell similar to sandalwood. The lance-

shaped, somewhat fleshy leaves are between 1 and 8 inches in length.

Leaves are often crowded near the branch tips. Tiny white to purplish

pink flowers form along the stem near the leaves. Naio fruits are either

greenish-white to pink or purplish. These become ribbed when dry.

Naio is found at elevations from sea level to 7,800 feet in dry to wet

areas. This plant can adapt to a variety of habitats as long as the soil

is well drained. It prefers full sun. Once established, this hardy species

requires little maintenance.

Pruning: Maintenance pruning should be done carefully and only when

plants are vigorously growing. The prostrate form can be trimmed as a

ground cover.

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Irrigation: Naio is drought tolerant and requires minimal watering.

Supplemental watering should be provided immediately after outplant-

ing and during prolonged drought conditions. Overwatering the soil

can cause black sooty mold.

Fertilization: A slow-release fertilizer can be applied to young or pros-

trate plants every six months.

Common pests: This plant is somewhat vulnerable to ants, scales,

mealy bugs, spider mites, and aphids. Damage from naio thrips (Klam-

bothrips myopori) has been noticed on prostrate and upright naio plants

in the northwestern portion of Hawaii Island. To date, the naio thrip has

not spread to other areas in the Hawaiian Islands. This pest causes leaf

curling and gall-like deformations on leaves and tips of new growth.

Thrips are often difficult to treat because they live in leaf folds.

Common name: Pili grass

Scientific name: Heteropogon contortus

Origin: This grass is indigenous to the

Hawaiian Islands and also occurs widely

throughout the tropics and subtropics of

Africa, southern Asia, northern Australia and

Oceania. The species has also become a

naturalized weed in tropical and subtropical

regions in the Americas, East Asia and the

Pacific.

Special features: Pili grass is a tropical,

short lived (less than five years) perennial grass that grows in clumps

to a height of 5 feet and a spread of 2 to 5 feet. It recovers well and

thrives by frequent burning. Pili grass develops dark seeds with a single

long stem at one end and a sharp spike at the other, which are capable

of drilling the seed into the soil.

It can be used to control erosion on slopes up to 20°, and grows best

in full sun, but tolerates moderate shade. It is drought and wind toler-

ant, has a high tolerance to salt spray but not to high salt soils. Native

Hawaiians used pili to thatch huts.

Appendices

341

Pili grass can be planted from seeds or vegetatively. Commercial seed

production is very low and most small-scale establishment has been by

vegetative splits. However, when seed is used it is important to recog-

nize the existence of two dormancy processes: one for the first four

months after harvest and the other delaying germination up to about 12

months.

Although there are attempts to restore native populations in Hawaii, pili

grass has become a weed in certain areas of the tropics and subtrop-

ics of the American continent and in East Asia. Its spread is assisted by

the use of seasonal fires. This grass can form pure stands in dry areas

which are very difficult to walk through because of the sharp leaves, and

spiked seeds can cause potential discomfort or injury.

Mowing: None, but can be mowed yearly or bi-yearly to six inches to

encourage new growth.

Fertilization: Pili grows on a wide variety of well-drained soils, ranging

from sand to very fertile clay loams. It is less common on heavy clay

soils. It is well-adapted to low fertility, but does not tolerant extremely

low fertility, poor drainage or high salinity soils. Pili responds to moder-

ate applications of nitrogen fertilizer, but high levels of nitrogen can kill

the plants. Once established, pili grass should not need regular fertiliza-

tion.

Irrigation: Water pili grass well under dry conditions until it is well es-

tablished. Mature pili grass grows best under dry conditions but will also

thrive with regular irrigation. It will remain greener longer and looks

nicer with regular watering. It does not tolerate long periods of flood-

ing or constant waterlogging, but can tolerate a few days of flooding

on otherwise well-drained soils. Once established, pili grass stands can

remain un-irrigated in areas that get at least moderate annual rainfall.

Common pests and diseases: Pili grass is occasionally subject to at-

tacks by scale, mealy bugs, locusts and grasshoppers, but is otherwise

generally pest-free. Smut diseases can affect seed production and often

tillering behavior. Leaf rust is common on more mature leaves in some

locations. Herbicides, such as triclopyr-picloram mixtures and tebuthi-

uron, are used for woody weed and broadleaf weed control in pili

grasslands. Like most grasses, it is tolerant of 2,4-D, but susceptible to

glyphosate.

Pili grass acts as a host for a downy mildew which also infects Zea mays

(corn). Therefore, the use of pili grass near seed corn production areas

of Oahu may not be advisable.

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Common names: Lonomea,

aulu, kaulu, manele, ae, soap-

berry

Scientific names: Sapindus spp.

Sapindus oahuensis (lonomea, aulu)

Sapindus saponaria (manele)

Origin: The native soapberry trees in-

clude one endemic and one indigenous

Hawaiian species. The endemic species,

Sapindus oahuensis, occurs only on Kauai

and Oahu, while the indigenous species,

Sapindus saponaria, is found only on

Hawaii Island. Sapindus saponaria also

occurs in Mexico, South America, Africa, and the Pacific basin.

Special features: The endemic lonomea is a medium to large-sized

tree that can grow up to 50 feet tall. The bark is gray and has a rough

texture. The papery, dark green leaves are between 3 and 8 inches long

and have a prominent yellow midrib. The indigenous manele grows up

to 80 feet tall and often has a wide canopy depending on the climate

and growing conditions. It has pale brown bark that tends to fall off

when older. This species has shiny green, feather-shaped leaves about

2 to 6 inches long. Manele is one of the few native Hawaiian trees that

loses its leaves seasonally. Both Sapindus species have small, whitish

to cream-colored flowers that develop at the ends of the branches. The

dark brown-black fruits are oval, fleshy, leathery and about 1 inch long.

These trees are often referred to as soapberry because the fruit pulp

produces abundant suds that lather like soap when mixed with water.

The native Sapindus species are tough trees that grow best in full or par-

tial sun. Lonomea requires direct daily sunlight, while manele is adapt-

able to many climates. Soils must be well drained, with soil textures

ranging from sand to cinder and coral. The trees are best grown from

seed; the large black seeds need to be cleaned and scarified to germi-

nate readily.

Pruning: Dead branches and twigs can be pruned as needed. If trees

become infested with black twig borers, cut and remove infected

branches. Fallen fruits can become sticky or slippery in high traffic areas

and should be cleaned up.

Appendices

343

Fertilization: Foliar feed every three to six months with small amounts of

slow-release fertilizer to ensure healthy growth.

Irrigation: Lonomea is drought tolerant and does not require much

water once established. Water monthly during the driest months, but

normal rainfall is usually adequate in most locations during the re-

mainder of the year. Overwatering can result in stem rot. Manele is

also drought tolerant, but typically requires moister conditions than its

endemic relative.

Common pests: These trees are prone to ants, as well as scale, mealy-

bugs, whiteflies, aphids and other sucking insects. Manele is also

vulnerable to red spider mites. A standard systemic insecticide, such

as Orthene

or Merit

will work well to control sucking insects. Young

branches are also susceptible to attack by the black twig borer. Mature

trees are typically more pest resistant. The bark can be sprayed with an

insecticide to prevent attacks by the black twig borer. Quickly remove

branches that become infested. If additional treatment for the twig borer

becomes necessary, use a systemic insecticide to control the infestation.

Common names:

Loulu, Pritchardia palms

Scientific names: Pritchardia spp.

Pritchardia affinis (Kona, Hawaii Island)

Pritchardia hillebrandii (Molokai);

Pritchardia remota (Niihau)

Origin: There are 19 Pritchardia spe-

cies endemic to the Hawaiian Islands

and all are called loulu palms. Of the

Hawaiian species, only three (Pritchar-

dia affinis, P. hillebrandii, and P. remota)

are typically used in landscaping. Sev-

eral other commonly used palm species

are endemic to Fiji (Fijian fan palms).

Special features: Loulu palms vary in height from 20 to 130 feet al-

though most grown in Hawaii range 30 to 50 feet. The leaves are fan

shaped and the trunk is columnar, naked, smooth or fibrous, longitudi-

nally grooved, and ringed by leaf scars. The flowers and fruit are borne

in large clusters at the ends of long woody flower stems that, in some

Highway Manual for Sustainable Landscape Maintenance

344

species, are longer than the leaves. Loulu palms have course, wavy,

fan-shaped leaves about four feet across. They are emerald green to

grayish or bluish green on top and a waxy grayish green below.

The three endemic loulu palms typically used in landscaping grow best

in full sun and prefer moderately moist and well-drained sand, cinder

or coral soils. Due to the natural coastal habitat of loulu, it does very

well in low-elevation landscapes and tolerates some salt spray.

Pruning: The dead leaves, flowers and fruits can be removed in a land-

scape setting for a cleaner appearance. Dead leaves will stay attached

to the trunk for a long time if not removed on a regular basis. Prun-

ing will make them grow taller faster, especially if flowers and fruit are

removed.

Fertilization: Apply a complete palm fertilizer with minor elements. Be

certain that enough magnesium and potassium is present in the fertilizer

component. This is especially critical for a loulu in a pot. Magnesium

and potassium deficiencies are two of the most serious nutritional dis-

orders in palms. The deficiencies are characterized by bright yellowing

(chlorotic) on leaf edges or yellow streaking of the entire fronds. This

can be difficult to reverse. Applications of Epsom salt, or magnesium

sulfate (MgSO4), are good but do not last and usually wash out of the

soil in rainy periods. There are some very good slow-release fertilizer

spikes made especially for palms which contain a good balance of

minor elements with magnesium and potassium.

Irrigation: Loulu palms can withstand short drought periods, but should

be irrigated on a regular basis for best growth and appearance.

Common pests: Loulu palms are prone to damage from leaf roll-

ers, whiteflies, red spider mites and sugarcane borers. Rats will eat the

fruit. Apply systemic insecticides, such as Orthene

or Merit

, to control

insects.

345

Appendix B

Plant Care: Common Roadside Non-native

Species

Common name: Bermuda grass

Scientific name: Cynodon dactylon (Com-

mon Bermuda grass); C. dactylon x C. trans-

vaalensis (hybrid Bermuda grass)

Special features: Bermuda grass is the most

widely used turfgrass in Hawaii. There are

two forms of Bermuda grass: common and

hybrid Bermuda.

Common Bermuda grass is a pure breeding

species, but has many different selected vari-

eties that are referred to as “improved common Bermuda.” All forms of

common Bermuda can be planted from seed and remain true breeding.

One of the best common selections for Hawaii is Sahara.

Hybrid Bermuda grasses have all been developed from crosses between

C. dactylon and C. transvaalensis. There are many selected varieties

of hybrids, ranging from general utility and sports turf, such as Tiffway

419

to the “ultradwarf” hybrids, such as TifEagle

, that are only used

for golf greens. Bermuda grass hybrids do not produce viable seed

and must be sodded or planted from pieces of stolons (above ground

runners) or rhizomes (below ground runners). The most commonly used

Bermuda grass selections for Hawaii roadsides are a few improved

common Bermudas, and the hybrid Tiffway 419

in high visibility areas

with higher maintenance level.

Light: Both common and hybrid Bermuda grass grow best in full sun

and are very intolerant of shade.

Mowing: Important factors to consider in mowing any grass are how

often and at what height to mow. How often to mow is determined

mainly by the growth rate of the grass, and the setting of the mower for

mowing height. Mow often enough so that no more than 1/3 of the leaf

blade is removed during a single mowing. Mowing intervals generally

can be farther apart when higher mowing heights are used. However,

for purposes of turf maintenance in the rights-of-way, all mowing and

other maintenance activities are on a once every two weeks schedule.

Highway Manual for Sustainable Landscape Maintenance

346

Mowing height for common Bermuda grass is 1½ to 2 inches in rural

areas and 1 to 1½ inches in high visibility urban areas. All hybrid Ber-

muda grass should be mowed at 1/2 to 3/4 inch.

To prevent damage use proper equipment, such as rotary mower and

keep the blades sharpened on a regular basis. Weed eaters should only

be used to trim in narrow or other inaccessible areas. Do not use weed

eaters for mowing.

Fertilization: Bermuda grass requires more fertilization than other warm

season species. For Bermuda grass in the Landscape Maintenance Zone

(LMZ), at least two applications of a slow-release, high-nitrogen formu-

lation per year will be enough to maintain good health and a consistent

rate of growth. The recommended formulation of fertilizer will be made

available to you by the HDOT Engineer. Refer to Chapter 11 for details

about fertilizers.

Irrigation: Bermuda grass is among the more drought tolerant grass

species. They can survive long dry periods by going dormant, where

they turn brown and stop any active growth. The deep roots allow them

to recover when water is again available. Actively growing Bermuda

grass requires between 1 to 2 inches of water per week, either as rain

or irrigation, to stay green and healthy. Deep watering twice a week is

recommended for mature Bermuda grass stands to promote good root

development. The soil should be moistened to a depth of 12 inches with

each watering.

Common pests: All varieties of Bermuda grass can occasionally be

attacked by certain caterpillars, which are the larval stages of several

small moths. Armyworm and sod webworm are the most destructive,

chewing out large patches of grass in a short period. A small mite,

called Bermuda grass mite, is also a common pest causing the grass

blades to become stunted and dry out.

Control: Several treatments with systemic insecticides, such as Merit

and Orthene

, are effective controls when applied a month apart.

Appendices

347

Common name: Be-still

Scientific name: Thevetia peruviana

Special features: Be-still is a close

relative to Nerium oleander, and like

oleander, be-still produces a milky

sap containing a compound that is

extremely poisonous. All plant parts

are poisonous, especially the seeds.

Common symptoms of poisoning: numbness, burning of the mouth,

nausea, vomiting, abdominal pain and diarrhea. Others include

drowsiness, coma, occasional convulsions, and irregular heart beat.

In extreme cases, death can be caused by heart attack. If any of these

symptoms occur shortly after exposure to be-still, call 911 immedi-

ately.

Be-still is a fast growing evergreen tropical shrub or small tree that

grows to 10 to 15 feet. It blooms repeatedly all year round with yellow

or orange-yellow, trumpet like flowers and its fruit is deep red/black in

color. The fruit produces a large seed that bears some resemblance to

a Chinese “lucky nut.” The long leaves are green and lance-shaped

and are covered in waxy coating to reduce water loss, which is typi-

cal of oleanders. The stem is green and turns silver/gray as it ages.

Be-still can be grown as shrub or tree. It tolerates most kinds of soil

as long as it is well drained and situated in full sun in a wind shel-

tered area. Be-still is useful as a roadside landscaping plant as it does

not need much maintenance and thrives in hot conditions. It can be

grown from seeds or cuttings.

Pruning: Can be used as a hedge, or trained into small tree form.

Prune occasionally to maintain size and shape. Be careful to wear

protective clothing, gloves and eye protection. Dispose of clippings by

bagging and do not allow exposure to yourself or others.

Irrigation: Water on a regular basis, especially in dry locations, for

best growth and appearance.

Fertilizer: Apply a balanced slow-release fertilizer as needed to main-

tain slow growth and color. Requires pH range of 6.8 to 7.6 (mildly

alkaline) and grows best in sandy and coral soils.

Common Pests: This plant is attractive to bees, butterflies and/or

birds. No insect or disease problems.

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348

Common name:

Bougainvillea

Scientific name: Bougainvil-

lea spp. (over 300 cultivars and

hybrids)

Because many of the hybrids have

been crossed over several genera-

tions, it is difficult to identify many

of them. There is a lot of confu-

sion over the names of bougainvillea varieties and cultivars.

Special features: Bougainvillea often has spiny, cascading stems which

end with colorful bracts of red, orange, purple and other shades with

small white, inconspicuous flowers. Bougainvillea can be used in a mul-

titude of ways: as individual accent plants, as privacy or barrier hedges,

as cascading erosion control plantings on steep slopes, and some

varieties can be pruned into a single-trunk small tree like an ornamen-

tal. The growth rate of bougainvillea varies from slow growing to rapid,

depending on the particular variety and the location. They grow best in

full sun and somewhat dry, fertile soil. They tend to flower all year round

in Hawaii. Typically, bloom cycles are four to six weeks.

Caution: The sap of the bougainvillea can cause skin rashes similar to

poison oak/ivy. So, when working with this plant (e.g., pruning), caution

should be exercised to avoid skin contact with the sap (and thorns).

Pruning: Prune by shearing with power hedge shears to promote the

greatest growth and flowering, as bougainvillea only blooms on new

growth. Shearing is the method of removing the soft tips of young plant

stems to encourage fuller growth. Bougainvillea sends out multiple new

stems just below the sheared tip. To increase vitality, lushness, and color,

shear frequently. The best time to shear is after the flush of color or

flowering cycle (four to six weeks) is completed. Do not allow bougain-

villea to become woody and overgrown unless it is being used on steep

hillsides or other locations where it is intended to cascade and cover a

large area.

Fertilization: Bougainvillea roots are susceptible to burn from fertilizers.

Do not over fertilize. In this case, less is better than more. Bougainvillea

has good salt tolerance and does best with soil pH of 5.5 to 6.5.

Appendices

349

Here are some quick fertilizer tips:

ࢫ Use a low nitrogen and high phosphorus formulation with micro-

nutrients, as well as additional iron and magnesium. Too much

nitrogen will cause excess leafy growth and reduced flowering.

ࢫ Slow- or time-release fertilizers are good. Follow the fertilizer label.

ࢫ Plants grow best with small amounts of nutrients constantly available.

ࢫ Do not apply fertilizers to dry soil; water well after fertilizing.

Irrigation: The amount of watering needed is related to the climate, soil

type, plant size and weather conditions. Plant in well-drained soil.

Helpful guidelines:

ࢫ Bougainvillea is drought tolerant and requires very little water once

established. If overwatered, bougainvillea will not flower, may lose

leaves or wilt, or even die from root decay.

ࢫ Drought stress can stimulate flowering. Allow the soil to dry between

watering, but not bone dry, as bracts and foliage will drop.

ࢫ The first sign of wilting is the best indicator of over/underwatering.

ࢫ Irrigation should be infrequent but watering run times should be

long enough to thoroughly soak the soil.

ࢫ Avoid constant, light, and frequent watering. This will promote a

weak and shallow root system and prevent coloring.

ࢫ Do not allow bougainvillea to sit in water. This may cause bracts to

drop or stop blooming altogether.

Common pests: Common insect pests include caterpillars, mites and

aphids. The “bougainvillea looper,” a small caterpillar of a common

moth, is the most troublesome pest causing extensive chewing damage

to the leaves. Mites and aphids can become problems in overgrown,

un-pruned plants, causing damage to leaves by sucking juices. The

sugary excretions from aphids often result in development of black sooty

mold on the leaves.

Control: Insect pests are best controlled with periodic foliar and soil

applications of systemic insecticides. Orthene

and Merit

are the best

choices. “Leaf spot” can be a problem if foliage or soil stays too wet,

especially in cool weather. Treat with fungicides; correct excessive over-

head watering.

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350

Common name: Coconut palm

Scientific name: Cocos nucifera

Special features: Two forms of coconut

palms are found in Hawaii. The common

form has a slender, often slightly leaning,

ringed trunk that can reach a height of 100

feet. The trunk is thickest at the base and

may show some sections of narrowing as

the tree grows taller. These narrowing areas

(called pencilling) result from some environ-

mental stress, often long periods of drought

during earlier years of growth, but are not

necessarily weak spots on the trunk.

A smaller form known locally as Samoan coconut has a shorter, thicker

trunk that grows no higher than 40 feet. It has larger, wider fronds and

bears large bright green fruit.

Pruning: Remove old fronds that hang lower than 90° (approximately

horizontal). Remove dead, dying, damaged and diseased fronds. De-

veloping coconuts (fruits) and flower clusters of both forms of coconut

palms should be removed on a regular basis. Take care not to cut too

close to the inner cone at the top of the trees. A wound can make the

tree more prone to fungal infection that will eventually kill the palm (see

pest section below). When feasible, tree trimming should be done dur-

ing dry weather.

Fertilization: Coconut palms do not grow well under heavy nitrogen

fertilization. Apply a balanced complete formulation, such as 16-16-

16, containing a high percentage of slow-release nitrogen and at least

2% magnesium. Early yellowing of the older fronds can be caused by

a magnesium deficiency; therefore, the need for a magnesium supple-

ment. Coconut palms have good salt tolerance at the root zone, but are

subject to salt spray damage on the fronds unless washed off periodi-

cally.

Irrigation: Palms do best in sandy, well-drained soils and should get

regular watering. The slender palm roots grow shallow in the soil and

spread far from the trunk. They do not require the deep watering that

some other trees need. Overwatering can lead to disease problems.

Appendices

351

Common pests: A fungal disease called “palm heart rot” is the most

serious pest problem. It has become a major factor in the demise of

mature coconut trees in Hawaii and has devastated coconut stands on

Kauai and Oahu. Coconut plants of all ages can be infected with this

disease.

Cause: Phytophthora fungus is relatively new to Hawaii.

Symptoms:

ࢫ The early stage is characterized by the drop of young coconut fruits.

ࢫ The stem end of small, young fruits or the entire coconut is dark

and rotten.

ࢫ Larger, immature or mature green fruits have brown, mottled, ir-

regular to circular patterns.

ࢫ Heart rot of the plant (a rot of the growing point at top of the trunk)

becomes evident as the youngest emerging spear leaf dies.

ࢫ Eventually all leaves are killed and the palm dies.

Spread: The disease is slow in development, and early stages of infec-

tion may be difficult to detect. The disease can be spread by the move-

ment of infected nuts and transplanted trees. Because transplanting

coconut is a common landscaping practice in Hawaii, symptomless but

infected trees may be transported great distances.

Tree pruning operations can also spread palm heart rot by carrying

fungal spores from diseased plants to healthy plants on contaminated

trimming equipment and tools. Wounds to the top growing heart of the

palm caused by careless pruning can also spread the disease. Insects,

birds and rodents can also spread the fungus by carrying spores or

infected palm tissue.

Prolonged rainy periods favor disease development and spread, as well

as over watering in combination with too much nitrogen fertilization.

Control: Fungicides and other pesticides are not effective. Diseased

trees and nuts should be removed and burned at the first signs of infec-

tion. The presence of infected host tissue is a serious threat to healthy

coconut trees in the surrounding area. Diseased plants keep the fun-

gus for many months, even after the plants have died. Tools should be

cleaned, then immersed in a disinfectant (e.g., rubbing alcohol) after

trimming operations on each tree are finished, especially at sites known

to have the disease.

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352

Common name: Fijian fan palm

Scientific name: Pritchardia pacifica

Special features: Fijian fan palms are

medium-sized palms that reach between

20 and 30 feet in height. The fan-shaped

fronds (or leaves) are coarse, pleated and

about four feet across. They are covered in

whitish-brown fuzz when young but older

fronds are mostly hairless. The trunk is co-

lumnar, smooth, unarmed and pale gray.

The flowers and fruit are borne in large

clusters at the ends of long woody flower

stems. The flowers are yellowish-green

and the round fruits are dark brown to blackish.

The Fijian fan palm is used widely in landscaping throughout the Ha-

waiian Islands. It is originally native to Fiji, Tonga, and possibly Samoa.

This species prefers full to partial sun and tolerates some wind. It grows

best in moist, but well-drained soils.