AGEH 28, Fall 2013Shasta College campus

Liquidambar styraciflua, sweetgum, liquidambar

• Monoecious—male & female flowers in separate heads; flowers small, greenish, without petals. fruit like a little spiked weapon (mace);

Liquidambar styraciflua, sweetgum, liquidambar

• Value: Easy, fast, fall color; resists oak root fungus

• Problems: must train to have strong central leader; roots heave sidewalks, fruits puncture bike tires (and feet)

• Many volunteer seedlings

An iron Head of a Mace. India, circa 18th century

Liquidambar styraciflua, sweetgum, liquidambar

• Native to Eastern US• ID: tree, 60 x 25 ft; leaf star-shaped, 5-7 pointed

lobes; corky wings on twigs

Pyrus calleryana ‘Bradford’Bradford pear

Rose family, Rosaceae

Pyrus calleryana ‘Bradford’Bradford pear

• Species native to China; cultivar developed in Maryland USA

• 50 x 30 ft, with strongly vertical limbs but no central leader; crotches weak

• Good fall color, first flowering tree to bloom, takes heat, grows well even in heavy clay

• Flowers smell bad• Invasive in North Carolina and other moist states

Platanus x hispanica London plane tree

Hybrid between the American sycamore (Platanus occidentalis) and Platanus orientalis of Eurasia

First recorded in Spain in the 17th century, where the Oriental & American Planes had been planted near one another. Leaf and flower characteristics are intermediate between the two parent species, the leaf being more deeply lobed than P. occidentalis but less so than P. orientalis, and the seed balls typically two per stem (one in P. occidentalis, 3-6 in P. orientalis). The hybrid is fertile.

Also known as P. X acerifolia

Platanus x hispanica, London plane sycamore family--Platanaceae

•ID: 80 x 40 ft; lvs maplelike, but alternate•Monoecious—male & female flowers in separate heads; flowers small, greenish, without petals. fruit like a little spiked weapon (mace);

Platanus x hispanica London plane tree, sycamore family

•ID: broad canopy, palmately lobed alternate leaves, flowers/fruits in spherical heads; peeling mottled bark, swollen petiole bases.

• Value: Fast growing, shade tree with wide spreading branches, fall color; beautiful bark

• Problems: roots heave sidewalks & may invade septic systems; may have large surface roots.

• The large leaves can create a disposal problem in cities. These leaves are tough and sometimes can take more than one year to break down.

• Pollen and leaf/fruit hairs highly allergenic to some!

Platanus x hispanica London plane tree

Catalpa speciosa, northern catalpabignonia family--Bignoniaceae

• Native to central US• Value: adapted to heat, cold, and western soils; flowers are showy; tree has lush tropical look

• Care: shape tree when young: shorten side branches and limb up when tall enough; moderate water

• Problems: protect from strong wind (leaf damage); messy

Catalpa speciosa, northern catalpabignonia family--Bignoniaceae

•ID: large tree; flowers like open snapdragons, in clusters; leaf very large, heart-shaped, sometimes slightly lobed.

•Fruits very long, hanging, beanlike

•Leaves opposite or whorled

•‘speciosa’ means ‘showy’

Catalpa speciosa, northern catalpabignonia family--Bignoniaceae

Fraxinus angustifolia ‘Raywood’ Raywood ash, claret asholive family--Oleaceae

Fraxinus angustifolia ‘Raywood’ Raywood ash, claret ash

Cultivar of a species native to the MediterraneanTree compact, 25-35 x 25 ft, fast-growing, small-leaved, lacy lookValue: fast growing, purple-red fall color; needs moderate waterProblems: Subject to branch dieback in CA, especially when drought-stressed

Ash dieback

Fungus dieback disease caused by Botryosphaeria stevensii (aka Diplodia mutila)

Leaves wilt, change color, die, limbs become bare

Can kill the whole plant

No control; provide adequate water for the trees

Fraxinus angustifolia ‘Raywood’ Raywood ash, claret ash

ID—• dioecious; • opposite, pinnately

compound leaves; • fruit a winged samara

(rarely found on this cultivar.)

• ‘chocolate drop’ axillary buds, as in Oregon ash

• angustifolia means ‘narrow-leaved’

Morus alba, white mulberrymulberry family--Moraceae

Morus alba, white mulberry

• 30-50 ft high and wide• Value: broad-canopied shade tree,

tolerates desert heat, alkaline soil, seacoasts; often pollarded

• Problems: sooty canker disease; heavy surface roots; needs moderate water to look its best. Fruits are messy and staining; pollen causes hay fever

• escapes into moist places, so plant “fruitless” males

Morus alba, white mulberry

Native to China--food of the silkworm, source of the ancient Silk Road

Morus alba, white mulberry

Silk fiber being made

Morus alba, white mulberryID:

leaves simple and alternate, variable shape--lobed on young trees, and less lobed or not lobed on older trees

most references call this a dioecious species—however, California Rare Fruit Growers say this:

Mulberry trees are either dioecious or monoecious, and sometimes will change from one sex to another. The flowers are held on short, green, pendulous, nondescript catkins. They are wind pollinated. In California mulberries set fruit without pollination.

Flowers inconspicuous, females make lots of bland purple fruit that stains; males make lots of allergenic pollen

‘alba’ means ‘white’

Prunus cerasifera ‘Thundercloud’, purpleleaf plum

rose family--Rosaceae

Prunus cerasifera ‘Thundercloud’, purpleleaf plum

Cultivar of flowering plum, native to Asia

Grows to 20 ft high and wide

Good purple leaf color

Does not like waterlogged soils (can fall over in a wet year)

May produce a crop of small fruit

Sometimes called cherry plum—’cerasifera’ means ‘cherry-bearing’

Prunus cerasifera ‘Thundercloud’, purpleleaf plum

May produce a crop of small fruit

Sometimes called cherry plum—’cerasifera’ means ‘cherry-bearing’

ID:Small tree with alternate, simple, finely serrate, purple leaves; many five-petaled pink/purple flowers in spring

Ginkgo biloba, ginkgo or maidenhair tree

gingko family--Gingkoaceae

Ginkgo biloba, ginkgo, Origin: China; family Ginkgoaceae; “living fossil” (remnant of plants living 270 million years ago; this is a GYMNOSPERM, related to conifers!)Native in the wild? No wild sites are known. The living ginkgos in China may have been tended by monks at sacred sites for the last 1000 years; rediscovered by Europeans in 1690 in Japanese temple gardens.

Ginkgo biloba, ginkgo, maidenhair tree, “silver apricot”

Value: growth slow; gold fall color, lovely foliage; wood strong, doesn’t heave, resists oak root fungus, tolerates air pollution; long livedPlant male cultivars (fleshy female seeds smell very bad); water young trees until establishedUse: Street tree, lawn tree; Forms: Some spread, some erect; gawky when young,

Ginkgo biloba, ginkgo

ID:leaf fan-shaped, often lobed;dioecious (sexes on separate trees)Not a flowering plant but a gymnosperm‘Gingko’ Chinese for ‘silver apricot’‘biloba’ means ‘2-lobed (the leaves)

Betula pendula, white birchbirch family--Betulaceae

Betula pendula, white birch,

• Native to Europe & western Asia• Value: fall color, white trunk,

delicate weeping foliage• Needs: sun, water, fertilizer, too

greedy for lawns• Problems: Prune in summer/fall to

minimize sap bleed• Susceptible to attack from bronze

birch borer--other birches better resist this insect

Betula pendula, white birch

• ID: Tree 30-40 ft, branches pendulous (weeping)

• Trunks white with black furrows

• Leaves diamond-shaped, doubly serrate (the teeth have teeth), tapered to a point

• ‘pendula’ means ‘hanging’

Betula pendula, white birch

• Monoecious; female and male flowers in separate catkins

• catkin n. A usually dense, cylindrical, often drooping cluster of unisexual apetalous flowers

Ripened female catkins

Cercis canadensis, eastern redbudpea family--Fabaceae

Cercis canadensis, eastern redbudpea family--Fabaceae

• Native to Eastern US forests; 25 ft x 25 ft

• Grow: in sun or part shade; needs water; good for watered gardens

• Valued for the 4 Fs: flowers, fruit, foliage, fall color; effective as understory tree, against dark conifers; better bloom with winter chillPrune in dormant season, or right after bloom

Cercis canadensis, eastern redbudpea family--Fabaceae

• ID: small tree or multi-stemmed shrub• heart-shaped leaf with pointed tip; • pink pea flowers emerge before leaves• Flat pea pod fruits

Cercis occidentalis, western redbudpea family--Fabaceae

Cercis occidentalis, western redbud• Native to California foothills

below 4000 ft.• Multistemmed shrub to 18 ft.• Leaf blue-green, kidney-shaped• Value: the 4 Fs; fall color yellow

to red (peachy)• Very drought tolerant; best in the

rarely watered garden (needs water the first summer or two); stunning along freeway

• Resistant to oak root fungus

Triadica sebifera (=Sapium sebiferum)Chinese tallow tree

spurge family--Euphorbiaceae

Triadica sebifera, Chinese tallow treeNative to Asia; Value: good fall color (select in fall); graceful fluttering foliage; resists oak root fungusCare: moderate waterProblems: Milky sap poisonous if ingested!!self-seeding pest of wetlands in Sacramento Co., Shasta College campus, and in eastern US

Triadica sebifera,Chinese tallow tree

ID: 30-40 x 25-30 ft; crown dense and round;leaves simple, alternate, diamond-shaped, entireMonoecious; male and female flowers in the same spike—females at base of spike, males aboveFruit a fleshy capsule with 3 large white seeds

‘sebifera’ means ‘tallow bearing’

Acer buergerianum, trident maple

Acer buergerianum, trident maple

Native to China, Japan; maple familyID: 20-25 ft high and wide (upright); lvs 3’’ wide, 3-lobed, glossy green, pale below, oppositeValue: fall color ( buy in fall leaf), flaking bark; good for patio and bonsaiCare: moderate water; prune in summer to minimize sap bleed

Acer buergerianum, trident maple

Forms: Sango kaku, coralbarkRed Dragon: holds red color thru summer

Acer palmatum, Japanese maple

Acer palmatum, Japanese maple

Deciduous arborescent shrub from Asia (Japan and Korea)ID: many-stemmed; leaf star-shaped, valleys deeper than sweetgum, 5-9 lobes, toothed; propeller fruits (double samara)Value: 4 Fs; young lvs red, winter branches green or red; good in shade, resists oak root fungus; good in containers (wider than tall)Care: water moderate, wind and sun tolerant, but in CA need protection from wind, heat, drought, so… grow in filtered shade, use on N walls; fancy grafted varieties touchier (finer leaf burns more)

Acer palmatum, Japanese maple

“Common seedlings have uncommon grace.”

Maple family (Aceraceae)

Trees or large shrubs; fruit a double samara, wind-dispersed; lvs deciduous, opposite, usu. lobed

Cornus florida, Eastern dogwood

Cornus florida, Eastern dogwood

Native to Eastern US; dogwood family (Cornaceae)ID: 20-30 ft, flr clusters with 4 showy bracts; native form has white bracts, many cultivars pinkValue: flrs, fruit, fall color (not fragrant)Care: needs part shade, summer waterProblems: anthracnose disease

Cornus nuttallii, western dogwood

Pacific Northwest; dogwood family (Cornaceae)ID: 20-30 ft, flr clusters with 4 showy bracts; native form has white bracts, many cultivarsValue: flrs, fruit, fall colorCare: needs part shade, summer waterProblems: anthracnose disease

Cornus nuttallii, western dogwood

Pacific Northwest; dogwood family (Cornaceae)ID: 50 x 20 ft, flr clusters with 4 showy bracts; native form has white bracts, gray branches in pleasing horizontal patternValue: Not suitable for CA valley gardensProblems: anthracnose disease; there are now resistant hybrids with C. kousa (‘Starlight’)

dogwood anthracnose

anthracnose disease, caused by microscopic fungus Discula destructiva

Lesions: tan spots with purple margins; defoliate large parts of tree of Eastern and Western dogwood

Dogwood anthracnose and resistant dogwoods

Hybrid forms bloom later than Eastern dogwood because of Cornus kousa blood (C. kousa blooms in June)

Some dogwood forms bred to be disease resist: Stellar dogwood(C. florida x C. kousa, also called C. x rutgersensis)http://www.ces.ncsu.edu/depts/hort/consumer/quickref/trees/dogwood-stellar.html

Dogwood family (Cornaceae)

Trees and shrubs.Leaves simple, opposite, entire-margined, with pinnate veins containing persistent fibers (veins often arced).Flowers small, clustered, consisting of 4 petals and 4 stamens. The showy part is the 4-8 large bracts that surround the flower cluster.Fruit small, fleshy.

Chilopsis linearis, desert willow (CALIF NATIVE)

Chilopsis linearis, desert willow

Native to Calif and SW deserts; Catalpa family (Bignoniaceae)

ID:15-30 x 10-20 ft; willow-like leaves, catalpa-like flowers in spring

Value: flowers, hummingbirds love it, blooms first year; tolerates little or no water

(Parent of x Chitalpa taskentensis)

Chilopsis linearis, desert willow

Pistacia chinensis, Chinese pistache, cashew family, Anacardiaceae

Pistacia chinensis, Chinese pistache, (Anacardiaceae)

• Fruits not edible!!• Leaves are even-pinnate• Brilliant fall color, even in mild climates• Resistant to oak root fungus• Good street tree, shade tree• Abundant volunteer seedlings : (

Gleditsia triacanthos ‘Sunburst’, sunburst honey locust

Gleditsia triacanthos, sunburst honey locust

• Needs moderate water• ID: leaves 2x pinnate, yellow in spring• Problems: roots heave pavement• Pests: honey locust borer; mimosa

webworm• Hort forms are thornless (species is

thorny); ‘Sunburst’ has yellow new growth (turns green in summer); defoliates in drought

Robinia pseudoacacia, black locust

• Native to E. US• 75 x 60 ft, with sparse open

branches, furrowed brown/black bark, thorny branches

• ID: leaves 1x-pinnate, leaflets 7-19; flrs white, fragrant, in hanging cluster 4-8 in.

• Use: Not a good street tree; don’t use because invasive…

Robinia pseudoacacia, black locust

• Wood rot-resistant, firewood and fenceposts (Lincoln??); acacia honey

• Pioneers brought it to Gold Country; it has gone wild (Old Shasta: keep or kill?)

• Can colonize the poorest soils, because root nodules fix nitrogen (makes its own fert); visible in spring all along Sac. R.

Robinia ‘Idahoensis’ or ‘Purple Robe’

• 40 x 30 ft.• These are forms of

hybrid black locusts, known as Robinia x ambigua

Robinia pseudoacacia ‘Frisia’, Frisia black locust

• Found in a Dutch nursery in 1935 and named after the province of Friesland

• Leaves 1x-pinnate; supposed to remain yellow all summer (but may green up in our summer heat)

Quercus rubra, Northern Red Oak

Quercus rubra, northern red oak

• Native to NE North America• ID: Tree to 75 x 50 ft., leaf 5-8 in., 3-7 prs of sharply

pointed lobes (hills), valleys (sinuses) less than halfway to midvein, hairs in angles along midvein; acorns covered 1/3 in shallow cup

• Needs: regular water• Value: shade, fast growth, fall color; roots deep so you

can garden under the tree; important timber tree in NE• Problems: a host plant of sudden oak death (terrible

disease of coastal CA); invasive in Europe (wet climates)

Pin Oak, Quercus palustris

• Hairy tufts in veins on underside of leaf

Pin Oak, Quercus palustris

• Known from Southeastern Canada and Eastern United States

• Found in swampy woods

Quercus douglasiiBlue Oak

Leaves deciduous, bluish, subtle fall color; lobes shallow

Acorn fattish, cup shallow

Drought tolerant, shade intolerant

Watering will shorten their lives (oak root fungus, other diseases)

Firewood and fence posts

Quercus lobata, Valley Oak

• Largest Oaks in California

• Known from Shasta County to Los Angeles County

• Central Valley, Coast Range and Sierra Nevada foothills

Quercus lobata, Valley Oak

• Deeply lobed leaves• Need deep fertile soil

with a high water table

• Acorns from valley oak, a daily food source for most tribes of Native Californians

Zelkova serrata, Japanese zelkova

Zelkova serrata, Japanese zelkova

Zelkova serrata, Japanese zelkova

• Native to E. Asia• ID: tree to 60 x 60 ft.; leaf narrowly oval,

serrated; bark smooth and gray• Value: nice tree, fall color, resists Dutch

elm disease, so a good elm substitute; can become a bonsai

• Needs: some water; full sun to part shade

Dutch Elm Disease

Dutch Elm Disease

• Fungal disease from Asia, Ophiostoma (Ceratocystis) species; introduced into America and Europe; identified in Holland in 1920s

• Attacks elms• Devastated North American urban elms; some

wild elms still OK• Spread by bark beetles, through tree roots,

imported on timber• Resistant: Princeton elm, Liberty elm• Or… use Zelkova