Medium - Large Trees Flashcards
Common Horsechestnut
Aesculus hippocastanum
Aesculus hippocastanum, or the Common Horsechestnut, is a large deciduous shade and flowering tree. It grows in an upright form, 50-75 feet high with a 40-60 foot wide spread. It grows best in well-drained soil in a location where it will get plenty of sun. Prefers regular deep watering. It is an excellent tree thanks to its many ornamental features and unique leaf. The bark of the tree exfoliates in plates, revealing the orange undertones of the young bark beneath.
The dark green leaf is palmately compound is 4-10 inches wide with seven leaflets. Each leaflet wis obovate with a pointed tip. The pinnate venation pattern is very noticeable on each leaflet. The margin of each leaflet is doubly serrated. Aesculus hippocastanum leafs out early in the spring, but the fall color is a poor mixture of pale yellow and brown. When the leaves are on the tree, the Horsechestnut is easily identifiable from other trees.
The Horsechestnut has showy blooms in the middle of spring. The blossoms form on long panicles (5-12 inches) which emerge at the terminal buds of the branches. Each blossom is an inch or so wide. The blossoms are white, with highlights of yellow or pink. The blooms are very showy and will last for three to four weeks. Blooms are more profuse on portions of the tree that receive good amounts of sunlight.
By summer, the 2 inch chestnuts begin to form on the tree, encased in a green, spiky capsule. In the fall, the capsule turns brown and splits open to release the hard, reddish-brown seed. Th spent seed capsules become messy once they fall on the ground.
Landscape Use
It is a large tree that is best used as a shade tree and in large developments. Dirr discourages its use for modern residential lots, but I have seen plenty used on smaller lots in Utah and they look wonderful, in large part because our climate typically keeps the tree under 50 feet.
Points of Interest
If not watered deeply during the summer months Aesculus hippocastanum will develop leaf burn on the edges of the leaf. It will not damage the tree, but is not attractive.
Notable Cultivars
Aesculus x carnea Baumannii This cultivar has double blooming white flowers that last longer than the regular species. It produces no fruit.
Aesculus x carnea Briotti A smaller form of horsechestnut, it only reaches 40 feet tall and has an equal spread, creating a nice rounded shape. It has bright red flowers instead of the typical white blossoms.
English Hawthorn
Crataegus laevigata
Crataegus laevigata, or English Hawthorn, is a popular small flowering tree. Ir grows 15-20 feet high and wide, with rounded, but somewhat wild looking canopy. It grows slowly, forming a densely-branched canopy that often exhibits some twisted limbs that give the tree a gnarled and ancient look. It is extremely tolerant of soil and climatic conditions and will grow well almost anywhere once it has been established.
The bark of the tree is gray-brown and develops a very rough texture similar to that of an apple tree. The 2 inch long leaves have multiple rounded lobes and are reminiscent of a small maple leaf. They are dark green and have a finely serrated margin. They are arranged alternately on the stem. The small leaves give the tree a fine texture. Thorns form at the base of the leaves and, while smaller than the thorns found on many other species of Crataegus, they are still painful to grasp.
In the spring the tree is covered with small, single blooming white blossoms. The blooms are about half an inch wide and form on corymbs. They flowery shortly after the leaves have emerged and last for 3-4 weeks. They are extremely showy for a two week period at which point they are on par with any other flowering tree. Following the blossoming, small, 1/2 inch pome fruit forms at the end of summer. It turns red in color and is a popular treat for birds.
Landscape Use
English Hawthorn makes a beautiful specimen tree thanks to its mildly-tortuous growth and showy spring flowering. It is excellent to use as a lawn tree as well. Although its tolerant nature makes it ideally suited for use as a parking strip or parking lot tree, its thorns can be an unpleasant surprise to the unsuspecting pedestrian. Additionally, the fruit is not persistent, and can become a mess on the sidewalk.
Points of Interest
Hawthorn is susceptible to fireblight and also leaf spot.
Notable Cultivars
Crimson Cloud: Single red blossoms have a white center. Grows more upright than the regular species and has improved resistance to fireblight and leaf spot.
Paul’s Scarlet: One of the most beautiful flowering trees I have ever seen. The blossoms are double blooming with red coloring on top of the petal and light pink or white underneath. They form in clusters that are reminiscent of small roses. Very susceptible to both fireblight and leaf spot, but do admirably well here thanks to our dry climate.
Lavalle Hawthorn
Crataegus x lavallei
Crataegus x lavallei, or Lavalle Hawthorn, is a small flowering tree (20 feet tall and wide). It has a densely branched canopy and a rounded form. It grows slowly and has fewer and smaller thorns than many Hawthorns. It grows under most any conditions and has proven itself remarkable hardy and tolerant. It has fewer thorns than other species of Hawthorns.
The leaf is a dark green, ovate to lanceolate in shape, 2-4 inches long. The margin is serrated on the top 1/2 of the leaf. The leaf is mildly pubescent on the top when it first emerges, but as it matures it becomes glossy on top and quite pubescent underneath. The leaves are arranged alternately on the stem. In fall the leaves turn a rusty red color in the fall which is quite good for a Hawthorn.
The small white blossoms appear in mid-spring on corymbs, 2-3 inches wide. The flowers are showy and stand out against the dark green foliage. Orangish-red pome fruit ripens in fall. It is 3/4 inch in diameter and persistent, providing some winter interest.
Landscape Use
It is excellent to use as a specimen or lawn tree. Because it has less thorns and good persistent fruit, this is the best Hawthorn species for use as a street tree or in a parking lot.
Points of Interest
It is susceptible to fireblight and leaf spot.
Washington Hawthorn
Crataegus phaenopyrum
Crataegus phaenopyrum is a small to medium sized flowering tree (20-30 feet high and wide). Like other species of Crataegus
The leaves are 1-3 inches long and are triangular shade. The top of the leaf is a glossy dark green color, while underneath it is a pale creamy-green. In fall the leaves turn an attractive orange color. Unlike the species of Hawthorn from Europe, Washington Hawthorn does not have rounded lobes on the leaf, but rather has 3-5 understated pointed lobes. The margin is serrated.
The flowers are white and appear on corymbs in the beginning of summer. The flower display is short lived, blooming for just a little over a week. Bright red pome fruit ripens by fall and is held in large clusters. The ornamental fruit persists on the tree through winter - or until the birds have eaten it all.
Landscape Use
It is excellent to use as a specimen or lawn tree. Although its tolerant nature makes it ideally suited for use as a parking strip or parking lot tree, its thorns can be an unpleasant surprise to the unsuspecting pedestrian.
Points of Interest
Unlike the other popular species of Hawthorn, Crataegus phaenopyrum is native to the United States.
It is susceptible to fireblight and leaf spot.
European Beech
Fagus sylvatica
Fagus sylvatica, or European Beech, is a truly awe-inspiring tree. There are very few trees that would cause me to buy a house simply because it had a mature specimen, but this is one. Dirr rightfully describes it by saying: “There is no finer specimen tree; so beautiful that it overwhelms one at first glance.” A truly noble tree. It grows 50-60 feet tall and 40-50 feet wide, with a strong and a broad pyramidal form. It branches low to the ground, and a mature specimen is the perfect climbing tree. The bark is a smooth light gray colored. Where the branches join the trunk the bark will exhibit a wrinkled appearance.
The leaves are 3-4 inches long and ovate or elliptic in shape and arranged alternately on the stem. The leaf margin is commonly entire but may also be undulate or finely serrated. The pinnate venation pattern is very visible on the leaf and is often indented in the leaf’s surface. The color is a very dark and glossy green on the top of the leaf, and a lighter green color beneath. When the leaves are emerging in the spring the margins are pubescent. In the fall the leaves turn a bronze color that is uncommon in the landscape and quite attractive.
Green fruit forms by late summer. Triangular nuts are encased inside a spiny involucre (or husk). When the involucre bursts open it creates a form that one might mistake for some sort of thick flower. The petiole of the fruit has a leathery pubescent texture.
Landscape Use
Best used as a shade tree or as a specimen tree. It is not suited for use as a street tree or in other difficult situations.
Points of Interest
This tree is wonderful, unfortunately it is underused in Utah, and having tried to sell it to many people I suspect its slow-growth rate is to blame.
Notable Cultivars
Dawyck: A columnar form that reaches 80 feet tall and only 20 feet wide The leaf is dark green.
Dawyck Purple: A purple-leaved form of Dawyck.
Tricolor One of the most unusual trees. I have more requests for this tree than any other - but its limited supply and slow growth rate make even the smallest specimens expensive. The leaf is a dark purple-green while the margin has interweaving shades of light and bright pink.
Asplenifolia: A delicate and lacy tree with a very fine texture. The leaves are long and deeply cut, creating a fern-like texture.
Pendula: A truly stunning tree with a beautiful weeping form and deep green leaves. It can reach 60 feet high with an equal spread.
Purpurea Pendula A small, weeping form with purple leaves. Reaches ten feet tall.
Rhoan The most vigorous and hardiest Beech cultivar. The leaves are a purplish-copper color and have an undulating margin. It has a good rounded form and can reach up to 40 feet tall.
American Sweetgum
Liquidambar styraciflua
Liquidambar styracifula, or American Sweetgum, is a large deciduous shade tree that grows quickly but is marginal in our climate. Once established the tree will do fine, but many young tree experience significant winter kill for the first few years. It has a single main leader that provides the tree with a good symmetrical form. When young the tree exhibits a pyramidal form, but matures to an upright oval form. It can reach 60 -75 feet high and about 2/3 that as wide. The bark has prominent vertical stripes of light brown and silvery gray. The pattern becomes less prominent as the bark matures, but it is still visible.
The leaf is is a beautiful star shape with 5 or 7 long triangular lobes. The leaf is 4 to 7 inches wide and long with a margin is finely serrated and. It is a dark green color on both the top and bottom of the leaf. In fall, the color is bright red, orange or even a purple color. It has some of the best fall color of any tree I have seen.
The fruit forms in the late summer and ripens in fall. They are 1 to 1 1/2 inches in diameter and extremely spiny. They emerge a green color, but turn a deep brown and harden before winter. They persist on the tree into winter, but a good number will drop. As a child I enjoyed using these as projectiles, though I did not enjoy it as much when I was on the receiving end.
Landscape Use
Use as a shade tree or park tree. It needs ample room for root growth - so it is not suitable for use in parking strip or parking lot.
Points of Interest
They are extremely pokey, and I would never walk under a Sweetgum barefoot. I saw a subdivision in Washington where they used Sweetgums as the lawn tree in front of every house. I am curious if the landscaper or developer has been sued out of business by homeowners who children have had their feet impaled by the Sweetgum balls.
Eastern Poplar or Cottonwood
Populus deltoides
A useful tree, though somewhat of a trash tree. Populus deltoides, or Eastern Poplar or Cottonwood, is an extremely fast growing tree that will add 4-5 feet or more of height each season. It will eventually reach a height of 75-100 feet and 50-75 feet wide. It has a an upright, broadly vase-shaped habit, but the form is usually damaged by dead or broken limbs. The massive trunks are covered in gray bark that is deeply ridged, with very large and wide ridges and fissures. Although it will handle drought conditions once mature, it needs wet soil to get established and to thrive.
The leaves are 3-5 inches long with a triangular-ovate shape and arranged alternately on the stem. The margin of the leave has rounded serrations that may look undulate. The leaf is a glossy green color. In the fall the leaves turn yellow and often have some brown spotting on the leaf.
The fruit of the tree is a capsule, 1/3 inch long, that when it opens reveals a mass of cotton-tufted seeds. These are dispersed by the wind and will create white clouds of cotton in the air and masses on the ground. Allergy-sufferers despise this tree when it is seeding.
Landscape Use
Its quick-growth rate makes it the ideal solution for a quick-fix to a missing shade tree or visual screen. It should not be used within ten feet of a sidewalk, driveway or patio or the roots will buckle the hard surface. Additionally, do not plant near water lines or sceptic tanks, as the roots will invade these and damage them.
I recommend that people use Poplars as only a temporary tree. They are quick to grow and quick to die, and quick to become ugly and cumbersome. Plant the tree you really want at the same time as the Poplar, and once it has become sizable, remove the Poplar.
Points of Interest
It is an excellent choice for soil stabilization and is used extensively in riparian restoration projects.
Poplar will sucker profusely and can send up new starts quite a distance away from the main trunk.
Notable Cultivars
Siouxland A cottonless form of the tree. It has an upright rounded form, reaching 80-100 feet high and 30-40 feet wide.
Populus deltoides Afghanica or Theves Poplar Also known as Theves. It is columnar and upright. reaching 80 feet tall with a width of 10-20 feet.
Bradford Callery Pear
Pyrus calleryana
Pyrus calleryana or Bradford Callery Pear is a popular flowering tree used extensively throughout the country. It grows 30-50 feet high and 20-35 feet wide, forming an upright-rounded form. It has a medium or fast growth rate. The bark is a grayish-brown color with prominent horizontal lenticels.
The flowers emerge in early spring before the leaves emerge. They are very attractive and have a faint odor. People seem to either adore or hate the scent of the blossoms. The flowers are white and form in 3 inch wide corymbs. It is one of the showiest blooming trees with the flowers covering the tree. Following the blossoms, small pome fruit, 1/2 inch in diameter, forms on the tree. It is green-brown color.
The leaves are ovate, 1 1/2 - 3 inches long and a glossy dark green. The leaf is somewhat thick and leathery feeling. The margin of the leaf is crenate. In the fall the leaves turn an attractive mixture of purples, reds and oranges.
Landscape Use
Because it handles poor soils well and has showy blossoms, it is very popular street tree and parking lot tree. It can be used as a shade tree or lawn tree as well.
Points of Interest
Because the branches emerge at a tight angle from the trunk, many flowering pears are marred by the loss of main branches due to winds or snowloads. I have seen flowering pears literally break in half down the middle of the tree.
Flowering pears are also considerably susceptible to fireblight.
Notable Cultivars
Aristocrat: It has an upright form growing to 35 feet high and 15 feet wide. It is a good selection for street trees because of its upright branching habit. It tends to have less branch breakage because the limbs branch at less of an angle.
Capital: A very tight and columnar form. It grows to 30 feet tall and only 8 feet wide.
Chanticleer: It has a good pyramidal form growing 35 feet high and about half that as wide.
Autumn Blaze: It has an upright pyramidal form and is the most cold-hardy of the flowering pears. Has bright red fall color.
European Mountainash
Sorbus aucuparia
Sorbus aucuparia, or European Mountainash, is a small to medium tree. It grows 20-40 feet high with 15-35 foot spread. It has a good ovate and rounded form. It prefers to grow in well-drained soil and performs well in sun or part-shade. It is a quick growing tree, but short lived. The bark is an orangish-brown color and has prominent horizontal lenticels.
The leaves are pinnately compound, 5-9 inches long and a dark green color. There are 9-15 leaflets, 3/4 - 2 1/2 inch long oblong or lanceolate in shape with a serrated margin, but usually entire on the lower third of the leaf.
White flowers appear in early spring. They are held on 3-5 inch flat corymbs. The flowers are somewhat showy, but do not appear profusely. In the sumer, large clusters of 1/4 inch in diameter pome fruit appear on the tree. The fruit is a bright red or orange color. The fruit is more showy than the flowers.
Landscape Use
It has the perfect size and form to be used as a lawn tree or small shade tree in today’s small residential lots.
Points of Interest
It is very susceptible to fireblight and the leaves will quickly burn if not watered regularly.
Flowering pears are also considerably susceptible to fireblight.
Notable Cultivars
Cardinal Red A quick grower with a good upright form. The leaves have a silver tinge beneath them. The fruit has a very good red color.
Common Baldcypress
Taxodium distichum
Taxodium distichum, or Common Baldcypress, is a tall deciduous conifer. It grows 50-70 feet tall and 20-30 feet wide. It has a conical form when young, but can develop a more spreading and flat-topped when old. It prefers to grow in moist soil, and is perfectly happy to grow in swampy soil. Where the soil is consistently wet the tree can develop knobby surface root projections called knees. The bark is a reddish brown color with a fibrous texture.
The needles are arranged on either side of a tender center stem called a branchlet. The needles are flat and pale green in color. They are 1/3 to 3/4 inches long. In the spring the needles may be blushed with a yellow color. In the fall the needles turn an orange color before dropping. Many people mistakenly believe the Baldcypress is sick and dying when the needles turn color and begin to drop in the fall.
One inch globular cones form on the tree and ripen in a single year. The cones are green when young, and then turn brown when they open. When closed, the cone looks like an unusual sports ball, with irregular plates and visible seams crisscrossing its surface.
Landscape Use
Use in extremely moist areas, such as lowlands, marshes and riparian areas. A good choice for parks and other large properties where.
Chinese or Lacebark Elm
Ulmus parvifolia
Ulmus parvifolia, or Chinese or Lacebark Elm, is a vigorous and large shade tree, reaching 40-50 feet high and wide. It has a good round form that has a very slight weeping habit. Other Elm species, particularly the American Elm, have been beloved for centuries and used extensively in nearly every situation imaginable. Unfortunately, Elms are so ravaged by disease that you are really playing Russian roulette by planting one. Lacebark Elm is more resistant to many of the prominent Elm diseases, but if a tree ever becomes stressed there is a good likelihood that it will not recover.
The 3/4 to 2 1/2 inch long leaf is obovate and dark glossy green in color. The plentiful veins are pinnate in arrangement and stand out from the leaf. The margin is serrated and the leaves are arranged alternately on the stem. In the fall the leaves will turn a yellow, orange or red color with a great deal of variation in the hue.
The bark is very ornamental. It exfoliates in small plates similar to the Planetree. Color variations of browns, olive green and orange are visible on the tree. The samaras are rounded, 1/3 inch wide and notched at the bottom. They form in clusters and ripen in the fall.
Landscape Use
Use as a shade tree or lawn tree. Also suitable as a street tree.
Points of Interest
It has good resistance to Dutch Elm Disease and Japanese beetle.
Notable Cultivars
Frontier A smaller cultivar with a good vase shape. It grows 30 feet high by 20 wide.
Siberian Elm
Ulmus pumila
Ulmus pumila, or Siberian Elm, is a trash tree and you are learning it here primarily so you will know to avoid it. I recommend the removal of any Siberian Elm on your own terms before it causes damage or spreads disease to other more desirable trees. Dirr describes Siberian Elm as: “One of, if not, the world‘s worst tree.”
It grows vigorously, with little care for the conditions it is planted in. It can reach 50-70 feet high and 35-50 feet wide. The leaves are 3/4 - 3 inches long, ellipctic in shape with an oblique base and arranged alternately on the stem. The leaf is dark green and doubly serrated. Round samaras are 1/2 inch across and notched at the bottom.
Landscape Use
There is no suitable use for this tree other than as firewood.
Points of Interest
Where to start? Siberian Elm suckers and seeds constantly, it rains leaf leaf and branch litter, suffers major limb breakage from wind and snow (and possibly by just looking at it), elm leaf beetle, cankers, aphids, and dutch elm disease. Siberian Elm makes you regret ever planting it because it is extremely difficult to completely remove. The only effective way I have found is to apply potent systemic herbicides directly into the tree.
Japanese Zelkova
Zelkova serrata
Zelkova serrata, or Japanese Zelkova, is a large shade tree, 50-80 feet tall and and 40-60 feet wide. It forms a strong vase shape early and maintains that shape even when mature. It is a good replacement for Elm trees and is becoming increasingly popular. It is somewhat tolerant of soil and climate conditions, but performs better in well-drained soils with regular watering. The bark is a cool grey color with prominent lenticels. The bark exfoliate in small patches to reveal orange undertones.
The dark green leaf is ovate, 1-2 inches long and arranged alternately on the stem. It has very visible venation in a pinnate pattern on the leaf. The margin is regularly serrated. In fall the leaves turns a mixture of yellow, orange, red and brown. The fall color is good on some trees but there is a great deal of variation between individual specimens.
Landscape Use
It is a good selection for a lawn or shade tree. Its good vase shape makes it an ideal selection for street trees or for use in parking lots.
Points of Interest
It is susceptible to Japanese beetle but has good resistance to Dutch Elm Disease.
Notable Cultivars
City Sprite: A small cultivar of Zelkova, it grows 25 feet high and 18 feet wide. It is a bit more oval in shape. The fall color is yellow. A very good selection for a street tree, especially under power lines.
Village Green: A large variety growing 50-60 feet tall. It grows quickly and vigorously, especially when young.
