ulmus

( UHL - muss )

At-A-Glance Information

This genus, commonly called Elm, includes deciduous and semi-evergreen trees that need full sun and regular water. They are known for their laundry list of health issues, though their previous reputations as wonderful shade trees have led to them still being planted and hybridized. These trees have a wide distribution in the Northern Hemisphere, where they are integral members in mixed forests. Use these trees to add interest, texture, and color to large gardens, as shade trees or street trees, or as specimens in the landscape.

ulmus Species and Varietals

The genus Ulmus is the type member of the plant family Ulmaceae and includes between 30 and 40 species. The best growing zones for Elm Trees vary depending on the species; For more information, see the descriptions below. To find your zone, click here: Zone Map.

Ulmus alata (Winged Elm, Wahoo)
This species of Elm is native to woodlands in southeastern and south-central United States. These trees are tolerant of a wide range of soils, and often have a very slow growth rate, putting on 5mm in trunk diameter per year. At maturity, these trees reach 43 feet tall with an equal spread. They are rarely cultivated beyond their natural range, and their wood is sometimes used to make high-end hockey sticks.

Ulmus americana (American Elm, White Elm, Water Elm)
This species is deciduous is best in zones 1-11 and 14-21 and is native to eastern North America. These trees quickly reach 100 feet tall and equal or greater width. Main branches are upright, and secondary branches are somewhat pendulous. Leaves are dark green, turning shades of yellow in the fall. Seeds are pale green and can make a mess. Disease resistant varieties of this species include 'Princeton' (upright to 65 feet tall), 'Valley Forge' (to 70 feet tall), and 'Jefferson' (vase-shaped to 70 feet tall).

Ulmus castaneifolia (Chestnut-Leaved Elm, Multinerved Elm)
These small, deciduous trees are native to China's broadleaf forests, and can reach 66 feet tall. Bark is thick, has a corky layer, and is longitudinally fissured. These trees are rare in cultivation.

Ulmus crassifolia (Texas Cedar Elm, Cedar Elm)
This deciduous tree is native to south-central North America, and also occurs in northeastern Mexico. These trees reach between 78 and 90 feet tall when mature, and have a rounded crown. Leaves fall from the tree late in the year, usually hanging on until early winter. A popularly grown variety is 'Brazos Rim'.

Ulmus davidiana (David Elm, Father David Elm)
This species is native to China, Mongolia, Korea, Siberia, and Japan, where it grows along streams. It was named for botanist Rev. Armand David, who first collected specimens of these trees. These trees are quite similar to Ulmus americana, but are smaller trees, only reaching 50 feet tall. This species produces relatively slender trunks that remain smooth-barked for a long while before becoming fissured with age.

Ulmus glabra (Scotch Elm)
This species is deciduous and native to Europe, growing well in zones 2-11 and 14-21. They can reach 120 feet tall with an upright habit and a spread of 80 feet. Leaves are toothed. Variety 'Camperdown' (Camperdown Elm) reaches 10-20 feet tall and wide, with weeping branches that reach the ground, forming a shade tent.
Ulmus Hybrid Varieties
This group of Elm Trees grow well in zones 2-9 and 14-21, and vary in size, shape and disease resistance. For more information on these varieties, read the descriptions below.
'Accolade'
To 70 feet tall and 60 feet wide, with arching limbs and a vase-like shape.
'Danada Charm'
Vase-shape, to 70 feet tall and around 60 feet wide, with a bit of a gangly habit.
'Frontier'
To 40 feet tall and 30 feet wide, with reddish-purple fall color.
'Homestead'
Reaches 55 feet tall and 35 feet wide, with an oval to pyramid form. 
'Patriot'
Forms a narrow vase that reaches 50 feet tall and half as wide.
'Triumph'
This variety reaches 55 feet tall and 50 feet wide.

Ulmus laevis (European White Elm, Fluttering Elm, Spreading Elm, Stately Elm, Russian Elm)
These large, deciduous trees are native to Europe. and form a relatively rounded crown. Trees reach about 100 feet tall, and leaves are shed a bit earlier than those of other species in the genus.

Ulmus lanceifolia (Vietnam Elm)
This species forms a very large tree, up to 150 feet tall, and has pendulous branches. These trees are native to a wide area in southern Asia, and are evergreen in tropical areas and deciduous in cooler northern regions. These trees are not cold-hardy, and are rare in cultivation.

Ulmus macrocarpa (Large-Fruited Elm)
This species can form either a tree or large shrub, and is notable for its tolerance to both extreme cold and drought. Individuals can reach up to 56 feet tall and have slender trunks with corky, fissured bark. Moderate resistance to Dutch Elm Disease.

Ulmus mexicana (Mexican Elm, Tirra)
This large tree is endemic to Mexico and Central America, and is most commonly found in cloud and tropical forested areas. They can grow to 82 feet tall, making them one of the tallest trees in Mexico. Foliage is green and glossy above, dull on the leaf undersides.

Ulmus minor (Field Elm)
This species is native to south Europe, Asia Minor, Iran, and the Baltic Islands, and usually grows in low-lying forested areas along riverbanks. These trees can tolerate summertime flooding as well as drought conditions, and reach about 98 feet tall. Crown is rounded and foliage is green. These trees readily reproduce through suckering.

​Ulmus parvifolia (Chinese Elm, Chinese Evergreen Elm, Lacebark Elm)
This species can be either deciduous or semi-evergreen, and grows well in zones 3-24. It is native to Japan, Korea and China and reaches 40-60 feet tall and 50-70 feet wide. These trees generally have an open, arching habit with weeping branchlets. Leaves are leathery and dark green, and these trees produce round fruit in fall. 

Ulmus pumila (Siberian Elm, Asiatic Elm, Dwarf Elm)
This deciduous species does well in zones A1-A3, 1-11 and 14-21, and is native to China and Russia. These trees can reach 50 feet tall and 40 feet wide, and have smooth, dark green leaves. Used as an erosion-control plant, as a screen or windbreak. This tree produces winged, papery seeds with a wide dispersal zone and is resistant to Dutch Elm Disease. This species can endure cold, heat, arid conditions and poor soil quality.

Ulmus rubra (Slippery Elm, Red Elm, Gray Elm, Soft Elm, Moose Elm, Indian Elm)
This medium-sized deciduous tree has a spreading crown and commonly reaches between 39 and 62 feet tall (exceptionally to 100 feet). Bark is greyish-brown and furrowed. The common name 'Red Elm' (and the specific epithet) refers to the reddish-brown heartwood of these trees.

Ulmus serotina (September Elm)
This North American species rarely exceeds 65 feet tall when mature, and has a rounded crown with pendulous to spreading branches. These trees are hardy to -23 degrees Fahrenheit, and can be grown in most soils (except in anaerobic or saline conditions). These trees are rare in cultivation.

Ulmus thomasii (Rock Elm, Cork Elm, Orme Liege)
These trees are native primarily to the midwestern United States, and was named in 1902 for David Thomas, an American civil engineer who first described the tree back in 1831. Trees in this species can live up to 300 years, and reach between 50 and 100 feet tall when mature, depending on the growing conditions. Bark is greyish brown and deeply furrowed.

Ulmus uyematsui (Alishan Elm)
This species is native to Taiwan, and reaches 82 feet tall. Bark is grey and fissured in mature trees. Leaves have a beautiful purple-red blush to them. These trees are rare in cultivation outside of their native range, but it is gaining in popularity due to its cold tolerance (the species is hardy to -4 degrees Fahrenheit). These trees do not do well in winter wet weather in clay soils.

Ulmus villosa (Cherry-Bark Elm, Marn Elm)
This species is native to the Kashmir region and reach about 82 feet tall when mature. Foliage is green and springtime flowers are apetalous. These trees are not commonly cultivated as garden ornamentals.

Ulmus wilsoniana 'Prospector'
This species is native to zones 3-9 and 14-21, and is native to western areas of China. It reaches 40 feet tall and 30 feet wide, with orange-red new leaves that mature to deep green and turn yellow in autumn. This species is resistant to Dutch Elm Disease and to Elm Leaf Beetles.

Caring for and pruning ulmus Trees

Ulmus trees prefer to be planted in a location in the landscape that receives full sun. They also love to have good air circulation, so ensure that there is enough space to accommodate the full size of the tree's canopy, which can stretch to between 40 and 70 feet when grown in gardens. Avoid planting Elm trees in areas of the yard that have heavy shade or poor drainage. These trees prefer well-draining fertile soil. They can tolerate a wide variety of substrates including clay or sand, but prefer a slightly alkaline to neutral pH (between 5.5 and 8.0). The best time to plant these trees is in either spring or fall. Apply a thick layer of mulch around the base of trees to suppress weed growth, increase soil moisture retention, and help to regulate soil temperatures. Water newly planted Elm trees regularly to help them establish a strong root system. Irrigate once or twice a week during the growing season in spring and summertime. Established trees are drought-tolerant, but still do appreciate deep waterings during times of extended drought.

Apply a generous layer of organic compost around the base of trees each springtime to support their new growth for the season. If trees seem to be struggling or are not growing well, they may also benefit from a feeding with a balanced, slow-release fertilizer in springtime. Avoid over-fertilizing trees, as this can make the tree more susceptible to common diseases like Dutch Elm Disease. Prune in late fall or winter when the tree is dormant, removing dead, damaged, diseased, or crossing branches and opening up the canopy to improve airflow and light penetration. This will also reduce the risk of disease. Avoid pruning in late spring and summer to prevent attracting Elm Bark Beetles (the spreaders of Dutch Elm Disease). 

Propagation

​Ulmus trees can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Elm tree, follow the instructions below:

Propagating Ulmus by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots. 
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Ulmus by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows. 
  2. Harvest your seeds. They are typically ready to be harvested in springtime, and usually will germinate in the same growing season. Seeds that ripen in fall will germinate the following spring. The timing that seeds will mature is affected by the species grown, the climate, and the weather patterns in the area around the tree. Green seeds are not viable; seeds whose papery covering are tan to brown and dried are mature and ready to be planted. Gather as many seeds as possible and place them in a paper bag or other container to bring them inside. Store them in a cool, dark, dry place until ready to work with them.
  3. Place harvested seeds in a sealable bag or container filled with moistened peat moss or sand, and place the container in the refrigerator for between three and four months' time. This cold-stratification period is typically necessary for seeds to germinate. After this time has passed, bring seeds out and sow them.
  4. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  5. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Elm tree seeds have a papery covering that turns brittle and tannish-brown when seeds are mature.
Elm tree seeds.

Problems and Pests

Elm trees can suffer from the following pests and diseases:
  • Dutch Elm Disease
  • Elm Leaf Beetle
  • Carpenterworm
  • Asian Longhorned Beetle
  • Scurfy Scale
  • Oystershell Scale
  • European Red Mite
  • Verticillium Wilt
  • Elm Yellows
  • Bacterial Wetwood
  • Black Spot
For more information on this list of pests and diseases, consult the following pages:
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Gallery

A Chinese Elm (Ulmus parvifolia) bonsai.
Elms make great shade and lawn trees.
The bark of mature trees is beautiful.
These are common street or parking lot trees, due to their impressive amount of shade cast.
Multi-trunked elms tend to not grow as tall, but have beautiful structure.
There are smaller garden varieties, including those with weeping habits, available for purchase at nurseries.

Videos

Lean about these great landscape shade trees.
How to identify an American Elm tree.

Resources

American Elm
Growing Elm Trees: Lean About Elm Trees in the Landscape
Ulmus - Elms
Care Guide for the Chinese Elm Bonsai
Wikipedia: Elm
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 642 - 643, Ulmus (Elm)
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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