Trees
This group of species includes trees that grow 30+ feet tall. Species are differentiated by branching pattern; size and shape of leaves; flowers and fruits; and bark characteristics.
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Resource Table
| Classification | Common Name | Other Common Names | Scientific Name | Resources | Videos | Weed ID slides ppt (AGR 375) | National Distribution Map | Look-Alike Species |
|---|---|---|---|---|---|---|---|---|
| Prohibited | Amur cork tree | Phellodendron amurense | Link | Phellodendron amurense | National Map | |||
| Restricted | Black alder | European alder | Alnus glutinosa | Link 1 Link 2 | Video | Alnus glutinosa | National Map | |
| Restricted | Black locust | Robinia pseudoacacia | UWEX Factsheet Link | Video | Robinia pseudoacacia | National Map | ||
| Not Regulated | Callery pear | Pyrus calleryana | Link | Pyrus calleryana | National Map | |||
| Restricted | Common buckthorn | Rhamnus cathartica | UWEX Factsheet Link | Rhamnus cathartica | National Map | |||
| Restricted | Glossy buckthorn | Frangula alnus | UWEX Factsheet Link | Frangula alnus | National Map | |||
| Prohibited | Princess tree | Paulownia tomentosa | Link 1 Link 2 | Paulownia tomentosa | National Map | |||
| Restricted | Russian-olive | Elaeagnus angustifolia | Link | Elaeagnus angustifolia | National Map | |||
| Prohibited | Sawtooth oak | Quercus acutissima | Link | Quercus acutissima | National Map | |||
| Restricted | Siberian elm | Ulmus pumila | Link 1 Link 2 | Video | Ulmus pumila | National Map | ||
| Restricted | Tree-of-heaven | Ailanthus altissima | UWEX Factsheet Link | Video | Ailanthus altissima | National Map | ||
| Restricted | White mulberry | Morus alba | Link | Video | Morus alba | National Map | ||
| Restricted | White poplar | Populus alba | Link 1 Link 2 | Video | Populus alba | National Map |
Species Summary Table
| Scientific Name | Common Name | Bark /Stems | Leaves | Flowers | Fruit | Leaf Division | Flower Color |
|---|---|---|---|---|---|---|---|
| Ailanthus altissima | Tree-of-heaven | Pale-grey bark; older bark with cantaloupe-like texture; light brown twigs | Alternate, 1-4’ long with 11- 25 toothless leaflets; strong odor of rancid peanuts | Dense clusters in upper branches of small, 5-6 petaled yellow-green flowers; May – June | Clusters of twisted papery samaras; green turning pink to tan | Pinnately compound | White to whitish |
| Alnus glutinosa | Black alder | Multi-stemmed tree; older bark brown-speckled with horizontal striations | Alternate, doubly-toothed leaves; rounded, glossy dark green, up to 4” | Male catkins appear in fall, remain on trees through winter; female flowers look like cones | Small oval samaras with wings reduced to narrow thickened ridges | Simple | Brown |
| Elaeagnus angustifolia | Russian-olive | New twigs densely covered in silvery-white scales, become smooth and shiny reddish- brown; sometimes have thorns up to 2” long | Alternate, lance-shaped, 1-4” long, 3/8 – ¾” wide, toothless; new leaves densely covered in silvery- white scales on both sides, upper surface becomes dull green | 1-3 funnel-shaped, ½” yellow flowers, 4 petal- like sepals; covered in silvery scales; June | Dull silver to yellow ½” oval fruit, covered in silvery scales when young | Simple | Yellow |
| Frangula alnus | glossy buckthorn | Grey-brown with white lenticels; new growth reddish-green; oldest bark grey; cambium greenish yellow; heartwood reddish orange | Alternate, simple, elliptic, toothless, 6-9 strongly parallel veins per side point to edge of leaf | Clusters of 2-8 in new leaf axils; 5- parted,yellowish- greenish white; 1/8”; May – September | ¼ - 1/3” berry turning from red to shiny black when ripe | Simple | Greenish white to white |
| Morus alba | White mulberry | Twigs reddish to orange- brown with raised lenticels; exude milky sap when cut | Alternate; up to 2-7 irregular lobes; egg-shaped; toothed; lighter green below with hairs along veins | Separate M + F catkins; M ¾ - 2” long; F more compact to 3/8” long; May – June | F fruit clusters ½ -1 ½” long, white to pink to red, turning purplish- black when mature | Simple | Green |
| Paulownia tomentosa | Princess tree | Lighter-colored shallow vertical fissures; twigs brown, speckled with white lenticels | Opposite; broadly oval to heart-shaped; 6-12” long, 5- 9” wide; hairy on both sides | Upright clusters 8-12” of 2” fragrant, light violet-pink tubular flowers; April – May before leaves emerge | Egg-shaped capsules 1- 2” long, 1 – 1 ½” wide; turn dark brown by winter | Simple | Lavender |
| Phellodendron amurense | Amur cork tree | Thick, corky, furrowed bark with bright yellow cambium | Opposite, 10-15” long with 5-11 leaflets; leaflets elliptical, toothless, dark green; smell faintly of citrus when crushed | Clusters of greenish flowers; late spring | Female plants have clusters of green fruits turn black in fall | Pinnately compound | |
| Populus alba | White poplar | Smooth, creamy white to grey; dark diamond-shaped lenticels; lower trunk with dark vertical ridges | Alternate, 1 ½ - 3”, rounded teeth; egg-shaped or lobed; white from woolly hairs below; flattened petioles | Separate M + F catkins; M 1 ¼ - 2 ½” long, tiers of red stamens with soft silky hairs; female 2-4” long; April – May | Green, conical capsule on catkins; splits in half to release cottony seed | Simple | Brown |
| Pyrus calleryana | Callery pear | Older bark grey-brown, slightly ridged | Alternate, 2-3” long; shiny; wavy, slightly toothed margins | 1”, white, smelly; April – May, before leaves emerge | Round, ½”, green to brown | Simple | White |
| Quercus acutissima | Sawtooth oak | Older bark grey-brown, deeply furrowed | Alternate, broadly lance- shaped, 2-8” long; dark green, shiny; edges toothed, bristled | Brown, inconspicuous flowers; May | Brown, oval acorns with cap that covers most of nut | Simple | Brown |
| Rhamnus cathartica | common buckthorn | Dark grey, shiny surface gets scaly with age; dark lenticels; cambium bright yellow-orange; heartwood deep orange | Mostly opposite, simple, egg-shaped, small teeth; 1 – 2 ¼” long, ¾ - 1 ½” wide; 3-4 prominent veins per side curve to tip | Clusters of ~10 in new leaf axils; 4-parted, yellowish green, <1/4”; June-July | ¼” berry ripens from dull green to shiny black | Simple | Yellowish green |
| Robinia pseudoacacia | Black locust | Older bark dark grey to grey- brown, deeply furrowed with forking ridges; young branches green, hairy; turning red-brown and smooth; pair of spines ½ - 3/4” at leaf scars | Alternate,, 4-12” long with 7-23 toothless, narrowly egg-shaped leaflets each ¾ - 2 ¼” long; smooth or finely hairy above; short hairs along major veins below | Showy hanging clusters 2-5” long with up to 30 fragrant, white pea-like flowers, ¾- 1” long; June | Thin, flat pod, 2-4” long; green maturing to reddish / purplish- brown | Pinnately compound | White |
| Ulmus pumila | Siberian elm | Older bark gray with interlacing ridges, deep furrows, inner orange bark sometimes visible | Alternate, lance-elliptic, ¾ - 2 ½”; toothed edges; veins straight; green with tufts of hairs in vein axils below | ½” clusters of 5-15 tiny flowers; light green to reddish outside; March - May | Flat, nearly round samara, 1/3 – 2/3”; hairless; tip cleft with 2 small lobes | Simple | Green to reddish |