Gymnocladus
( jim - NO - kla - duss )
At-A-Glance Information
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Commonly called Kentucky Coffee Tree, this deciduous species prefers full sun and regular water. These very large landscape trees are native to the eastern North America and southeastern Asia and provide year-round interest. They grow slowly when young, and moderately once they have established a strong root system, taking about 10 years to reach 15 feet tall. Flowers are greenish-white and inconspicuous, typically only blooming after long periods of warm weather. Use these trees as lawn, shade, or specimen trees in the garden. Take care when planting these trees in the landscape, as plant parts are toxic to humans, pets, and livestock if ingested. Even water sources contaminated with leaves or seeds can have toxic effects.
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Gymnocladus species and varietals
This small genus is a member of the plant family Fabaceae and includes six species. The genus name is derived from the Greek words gymnos (meaning naked) and klados (meaning branch). Gymnocladus trees grow well in zones 1-3, 7-10, 12-16 and 18-21. To find your zone, click here: Zone Map.
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Gymnocladus burmanicus (Dekang Tree) These wild trees are native to India, Myanmar, and Thailand. Individual trees reach up to 56 feet tall when mature, and produce green, divided foliage and fat seed pods. These trees are commonly harvested from the wild in their native range for use as a medicine and source of soap. Pods have a foul smell. |
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Gymnocladus chinensis (Chinese Coffeetree, Soaptree) Native to central China, this species of deciduous tree has very large bipinnate leaves that emerge purple and mature to green. These trees typically reach between 15 and 30 feet tall and wide, and produce irregular to rounded crowns. This species needs protection from cool, drying winds to perform well. Fall color is bright yellow. This is a great landscape tree that can take underplantings due to its light shade cast. |
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Gymnocladus dioicus (Kentucky Coffeetree, American Coffee Berry, Kentucky Mahogany, Nicker Tree, Stump Tree) These trees are native to the northeastern United States and southeastern Canada. Fast growing to 8-10 feet tall, and then slow-growing to 60-100 feet tall and 45-50 feet wide. Leaves are divided into leaflets, and emerge pink in springtime. Foliage when mature is deep blue-green. Casts light shade in summertime. Picturesque when bare in wintertime. Creamy to green-white clusters of flowers appear in spring. Female trees produce red-brown seed pods after flowers fade that persist through the winter months. Variety 'Espresso' is a great seedless male form. |
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Caring for and pruning gymnocladus Trees
Gymnocladus, or Kentucky Coffee Tree, is best grown in full sun. Choose a spot in the landscape that receives a minimum of 6 hours of direct sun each day. While these trees can tolerate some light shade, especially when they are young, they will perform better and grow faster in full sun exposure. They prefer well-draining soils but can tolerate a variety of soil types, including clay, loamy, and sandy substrates. They are adaptable trees that can take poor or compacted soils as well, making them a great choice for urban or low-maintenance landscapes. They prefer slightly acidic to neutral soils (with a pH of between 5.0 and 8.0). After planting, apply a thick layer of mulch around the base of trees to increase soil moisture retention, suppress weed growth, and regulate soil temperatures. Newly planted trees should be watered regularly during their first few years in the ground. This will help them to establish a strong root system. Mature trees are considered drought-tolerant and don't require regular waterings. Simply deep water during the warmer months of the year.
Pruning these trees is not typically necessary; they have a naturally irregular but handsome shape. Pruning should be used simply to remove dead, damaged, or diseased branches and should be done in late winter or early springtime, before new growth pushes out for the year. Avoid heavy prunings, as this can damage the tree and interfere with its natural growth habit. Make sure any pruning cuts are done cleanly and not too close to the main stem to avoid damaging the tree. Kentucky Coffee Trees require little fertilization; a simple application of organic compost once a year around the base of trees is sufficient to provide nutrients for the active growing season. If trees seem to be struggling, a balanced, slow-release fertilizer can be applied in springtime.
Pruning these trees is not typically necessary; they have a naturally irregular but handsome shape. Pruning should be used simply to remove dead, damaged, or diseased branches and should be done in late winter or early springtime, before new growth pushes out for the year. Avoid heavy prunings, as this can damage the tree and interfere with its natural growth habit. Make sure any pruning cuts are done cleanly and not too close to the main stem to avoid damaging the tree. Kentucky Coffee Trees require little fertilization; a simple application of organic compost once a year around the base of trees is sufficient to provide nutrients for the active growing season. If trees seem to be struggling, a balanced, slow-release fertilizer can be applied in springtime.
Propagation
Gymnocladus 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 Gymnocladus, follow the instructions below:
Propagating Gymnocladus by Cutting
Propagating Gymnocladus by Seed
Propagating Gymnocladus by Cutting
- 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.
- 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.
- 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.
- 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 Gymnocladus by Seed
- 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.
- Harvest your seeds in early springtime after pods turn brown. The seed pods on Gymnocladus plants are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
- Gymnocladus seeds have a hard coating that protects them, but this coating also makes it a little difficult to get them to germinate. We can help the process along by scarifying them with sandpaper (or simply rubbing them against an abrasive surface). Do this with as many seeds as you can; they will probably not all sow, and the ones that do will be of varying characteristics. The more seeds you plant, the more chances you will have to get the resulting shrub you want. Place your seeds in boiling water, and then let cool for 24 hours. Viable seeds will sink to the bottom, and non-viable seeds will float to the top. You can discard any seeds that float.
- 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.
- 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
Kentucky Coffee trees produce seed pods in springtime.
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Gymnocladus seeds are shiny and dark brown to black.
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Problems and Pests
Kentucky Coffee Trees can be somewhat messy, their pods and leaves decorating patios and other hardscaped areas in fall and winter. They are considered to be generally pest and disease-free, but can be susceptible to some common garden ailments, including:
- Leaf Spot
- Webworms
- Scale Insects
Gallery
These trees have a beautiful canopy shape.
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The foliage on Kentucky Coffee Tree is divided and green.
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A young Gymnocladus tree.
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This mauture Kentucky Coffee Tree casts nice shade for its underplantings.
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The flowers on these trees are white, and bloom in long panicles.
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Bark on mature trees is grey to light brown and fissured.
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Videos
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Learn about Kentucky Coffee Trees.
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Kentucky Coffee Tree.
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An introduction to these beautiful landscape trees.
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How to identify these trees in the landscape.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 349, Gymnocladus dioica (Kentucky Coffee Tree)
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