AGEH 28, Fall 2013Shasta College Arboretum

Fraxinus latifolia, Oregon ash olive family, Oleaceae

Fraxinus latifolia, Oregon ash olive family, Oleaceae

• Deciduous tree to 40-80 x 30-50 ft; native to Sierra Nevada, and N. Calif to BC

• ID: Lvs 6-12 ”, 5-7 leaflets, end leaflet larger than side ones; tree dioecious (sexes on separate plants); fruit a flat samara with a terminal wing, hanging in clusters

• Care: Sun, no irrigation when established; tolerates standing water in winter

• Value: fall color!!• Problems: leaf spot fungi even on healthy plants,

heart rot on older trees, various insects

Nyssa sylvatica, sourgum, tupelo; Nyssa family, Nyssaceae

Nyssa sylvatica, Sourgum, tupelo

Nyssa sylvatica, Sourgum, tupelo, Nyssa family (Nyssaceae)

• Native to eastern US; 30-50 x 15-25 ft

• Likes moist deep soil, will tolerate some drought, takes poorly drained, heavy soils

• Excellent shade tree; fruit sour, but attractive to birds; good fall color even in mild winter climates

• Fruit a drupe (like olive)

Albizia julibrissin, silk tree, “mimosa”

Pea family, Fabaceae

Albizia (Albizzia) julibrissin, silk tree, “mimosa”

• Native to Asia• ID: Tree to 40 ft, twice as wide as high

Leaves 2x pinnate, Flowers powder-puff, ‘Rosea’ has richer pink

• Value: Likes high summer heat; tolerates low water; makes shade; flowers fragrant, attract bees and hummingbirds•Problems: somewhat invasive in moist places; a bit messy,

Euonymus alatus, winged burning bush

Euonymus alatus, winged burning bush

FALL COLOR!!

Euonymus alatus, winged burning bush

• Native to northern Asia; needs moderate water• ID: leaves opposite, oval, 2 in., twigs usually with

corky wings• Tolerates full shade, but best color in sun or part

shade• Species plants can be large (20 ft); buy compact

forms ‘Compacta’, etc.; good against dark evergreens (brick walls???)

Invasive in wildlands where there is summer rain (by seeds)

Hibiscus syriacus, rose of sharon

Hibiscus syriacus, rose of sharon

• Deciduous shrub from E. Asia• 10-12 x 6-12 ft.; can be trained as small tree,

espalier• Likes heat, needs sun and moderate water to

bloom well

Hibiscus syriacus, rose of sharon

• Can seed around; buy good forms (sterile triploids: Aphrodite, Diana, Helene, Minerva);

• For larger flowers, cut back last season’s growth to 2 buds

Populus nigra ‘Italica’, Lombardy poplar

Populus nigra ‘Italica’, Lombardy poplar

• Native to Europe; grows 50-100 x 10-30 ft.• ID: tall and narrow; leaf slightly diamond-shaped

at base, narrowed to long tip, serrate• Value: Fast and tough; good for hot summer/cold

winter climates; yellow fall color; dramatic in the landscape; wooden shoes

• Problems: suckers profusely, heaves, clogs sewer pipes

Populus nigra ‘Italica’, Lombardy poplar

• Forms: ‘Italica’ is a male form, no seeds; female poplars produce lots of cottony fruit

Syringa vulgaris, common lilac

ID: shrub, to 20 x 20 ft; leaf heart-shaped (cordate); fragrant flowers

Syringa vulgaris, common lilac• Native to E. Europe• Needs: sun/ part shade; some

water; winter chill, neutral to alkaline soil (add lime if needed)

• Care: Must prune just after flowering (you have a week, maybe); also, prune out a few of the oldest stems each year to encourage new growth

• Forms: Zillions (hundreds) of varieties

Salix babylonica, weeping willow

Salix babylonica, weeping willow

• Tolerates poor drainage• Large tree (50 ft high and wide),

rather short-lived, with weak wood; not suitable for city lots

• Largely replaced in gardens by S. x sepulcralis ‘Chrysocoma’; there are also other better forms for this same look.

Taxodium distichum

Taxodium distichum, swamp cypress

Taxodium distichum, swamp cypress

Taxodium distichum, swamp cypress

•Native to southeastern US•100 ft in the wild, but garden trees 50-70 x 20-30 ft.

•Very tough, tolerant, deciduous conifers of great size, with shaggy bark and graceful sprays of needlelike leaves. Takes waterlogged or dry soils; good for streambank or lake edge.

Metasequoia glyptostroboides, dawn redwood

Metasequoia glyptostroboides, dawn redwood

•Native to China; thought to be extinct for millions of years but found again in 1940s.

•Deciduous conifer. Fast growth when young, to a pyramid-shaped adult of 90 x 20 ft. Likes moisture, so grows in lawns, but surface roots lift turf eventually. Winter form sometimes gawky.

•Resists oak root fungus.

Dawn redwood vs. swamp cypress

Dawn redwood vs. swamp cypress

Cornus stolonifera, redtwig dogwood & yellowtwig dogwood

C. s. ‘Arctic Fire’

C. s. ‘Flaviramea’

Cornus stolonifera, redtwig dogwood & yellowtwig dogwood

Native to n. Cal and north to Alaska

ID: multistem shrub 7-9 x 12 ft.

Spreads via underground stems and rooting branches

Leaves 1.5 – 2.5 in, oval, deep green; flrs small, white, in clusters; fruits white or bluish

Value: 4 Fs, esp. red or orange fall color, and red or yellow winter twigs

Cornus stolonifera, redtwig dogwood & yellowtwig dogwood

•Care: sun to part shade, regular water (streamside plant in the wild); cut back SEVERELY in late dormant season

•Use: thrives in coldest mountains, even in valleys of S. Cal, useful for streambanks, property boundaries, screen

•Names: aka red osier dogwood; Cornus sericea very similar

Forsythia x intermedia, forsythia

Forsythia x intermedia, forsythia

Origin: China, olive family

ID: 4-petal yellow flowers, vase-shaped or arching shrub; leaves oval with pointed tip, serrate; bark with lenticels

Forsythia x intermedia, forsythia

• Value: yellow flowers in early spring; tough; very cold hardy; can be forced by picking stems in bud

• Care: sun, moderate water; prune 1/3 of oldest branches to ground each year

• Forms: get good ones!

Sophora japonica, “popbead tree”J. pagoda tree, Ch. scholar tree

Sophora japonica, “popbead tree”J. pagoda tree, Ch. scholar tree

• Native to China, Korea, Japan• 60 ft high, 2/3 as wide• Use for park, shade• Leaves compound, alternate• Flowers pea-flower-shaped, white,

bloom in summer (August)• One of the 50 fundamental herbs

used in traditional Chinese medicine

• (aka Styphnolobium japonicum)

Symphoricarpos x chenaultii, coralberry

Symphoricarpos x chenaultii, coralberry

• Native to North America; this form is a hybrid of S. orbiculatus from eastern US.

• To about 6 ft; best used as a wild thicket for erosion control on steep banks, spreads by root suckers; needs part to full shade in hot climates.

• Cut stems nice for winter arrangements.• There is a one-foot dwarf ‘Hancock’ valued

as woodland groundcover.

Alnus cordata, Italian alder

Alnus cordata, Italian alder

•Native to Italy and Corsica• ID: 40 x 25 ft.; growth vertical when young; leaf heart-shaped, 4 in., glossy rich green; flrs = male soft catkins and female woody catkins (“cones”)

•Value: good near creeks, fast growth, flrs good display before lvs; favored in the SW

• “More restrained than A. rhombifolia.”

•White alder is our native tall alder

Liriodendron tulipifera, tulip treemagnolia family--Magnoliaceae

Liriodendron tulipifera, tulip tree

• Native to eastern United States• Tallest deciduous tree in the world

—200+ ft. in the wild• Yellow fall color, even in S. Calif.

• Flowers not showy, as carried high on tree; but beautiful up close. Starts blooming when 12-15 years old

• Likes deep rich soil, roots shallow so cannot garden under them

• Susceptible to Ganoderma root/butt rot fungus.

Liriodendron tulipifera, tulip tree

Because of its tall, straight trunk and wood that is soft, lightweight,

straight-grained, resistant to splitting, and easily worked, Native

Americans and early pioneers frequently hollowed out a single

log to make a long dugout canoe.

Its wood is sold commercially as “yellow poplar,” & used for

furniture, musical instruments, interior finishes, shingles, & boats.

Liriodendron tulipifera, tulip tree

Liriodendron tulipifera, tulip tree

• ID—tall straight growth, 4-lobed leaves like no other.

• ‘tulipfera’ means ‘tulip bearing’

Magnolia family (Magnoliaceae)

Ancient flowering plant group; some of the earliest fossil flowers found look like magnolias

Magnolia x soulangeana ‘Rustica Rubra’; RR saucer magnolia

More pix

Magnolia x soulangeana ‘Rustica Rubra’ Saucer Magnolia

10-25 x 10-15 ft; Value: spectacular bloom in deep pink before leaves; this form with spectacular fruits (pendent, rose pink, with red “seeds”) attractive to birds

Hybrid of M. denudata and M. liliiflora

Magnolia x soulangeana ‘Rustica Rubra’ Saucer Magnolia

Fruit a follicle, shaped like misshapen sausage from side; this is a view from below

What’s a follicle?

A follicle is a dry fruit, developing from a single pistil, opening along one side; magnolia fruit is an aggregate of follicles

(this magnolia fruit is typical of bull bay magnolia, not typical of saucer magnolia)

Wistaria sinensis, Chinese wisteria

Wistaria sinensis, Chinese wisteria

• VIGOROUS vine, beautiful but messy

• Invasive into moist areas • Most common wisteria in West• Leaves with 9-13 leaflets• Notice the direction of twining for

ID: Counterclockwise= W. sinensis; Clockwise= W. floribunda

• Plant toxic (esp seeds)• Prune in winter

Celtis australishackberry

Celtis australishackberry

Lagerstroemia indicaCrape Myrtle

Lagerstroemia indicaCrape Myrtle

• Colorful and long lasting flowers

• Blooms in the summer and autumn

• Panicles of crinkled flowers with crepe-like texture

Lagerstroemia indicaCrape Myrtle

• Bark shed throughout the year

Lagerstroemia indicaCrape Myrtle

• From China and Korea

• Huge variety of cultivars

• Best in mild climates that are not overly humid such as inland California and Texas

Crataegus phaenopyrum Washington Hawthorn

Crategus phaenopyrum Washington Hawthorn

• White to red flowers• Dense growth• Menacing thorns can

make an inpenetrable hedge

Crategus phaenopyrum Washington Hawthorn

• Red pea-sized fruits are relished by birds.

• Can be cooked into jellies and jams.

Malus zumi Radiant Crabapple

Malus zumiRadiant Crabapple

• Many different cultivars

• Hardier and more tolerant of wet soil than other stonefruit

• Most useful and least troublesome of flowering trees

• They can tolerate the heat

Spiraea japonicaGoldflame

Spiraea japonicaGlodflame

• New growth is bronze-red turning bright yellow, then eventually mid-green

• Dark pink flowers produced mid to late summer

• Easy to grow• Enjoys sunny spot in

moist well-drained soil