Cladrastis
( kla - DRAS - tiss )
At-A-Glance Information
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This genus of deciduous tree, known best for species Cladrastis lutea and Cladrastis kentuckea is native to Kentucky, Tennessee, and North Carolina, reaching 30-50 feet tall at maturity. These trees are commonly called Yellow Wood, and form a canopy that spreads out 15-25 feet. They prefer being planted in full sun and need regular water for best performance. Although they may not flower for the first ten years of life, when they do the flowers are spectacular. Blooms are white (though varieties exist with pink blooms) and blossom in dangling clusters that mimic Wisteria. They are followed by seedpods. These trees are wonderful for patios, terraces and lawn trees. Yellow Wood grows best in zones 2-9 and 14-16 (to find your zone, click here: Zone Map).
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Caring for and pruning Cladrastis Trees
Cladrastis trees prefer to be planted in a location that receives full sun (between 6 and 8 hours of direct sun every day), though they can also grow in places that get partial shade. They will flower and grow the fastest in full sun exposure. Make sure that there is enough space to accommodate the tree at its full size in the space chosen; these trees can reach up to 3-50 feet tall and just as wide. These trees also produce deep taproots, so there should be no pipes or other barriers to root growth under the planting area. They also do not transplant well, so make sure that the planting site is chosen very carefully to avoid the need to move it later on. Soil should be well-draining. If local soil is heavy or clayey, amend with plenty of organic material before installation. Cladrastis prefers a soil pH of between 5.5 and 7.5. They can tolerate alkaline soils, as well.
When planting, ensure that the root flare (the point where the roots start to flare out for root growth is slightly above the soil surface. For newly planted trees, soil should be kept consistently moist. Apply a 2-3 inch deep layer of mulch around the base of the tree after installation. After the first few years in the ground, these trees are considered moderately drought tolerant, and will be able to get by on only deep waterings during extended dry periods of the year. Avoid frequent, shallow waterings. These trees do not need fertilizing other than a yearly application of organic compost around the base of the tree. Pruning is also minimal, and should be completed in late wintertime or early springtime before new growth pushes out for the year. At this time, remove dead, damaged, or diseased growth as well as any crossing branches. These trees have a naturally attractive shape, and do not need additional shaping. Avoid heavy prunings, as it can cause excessive sap bleeding.
When planting, ensure that the root flare (the point where the roots start to flare out for root growth is slightly above the soil surface. For newly planted trees, soil should be kept consistently moist. Apply a 2-3 inch deep layer of mulch around the base of the tree after installation. After the first few years in the ground, these trees are considered moderately drought tolerant, and will be able to get by on only deep waterings during extended dry periods of the year. Avoid frequent, shallow waterings. These trees do not need fertilizing other than a yearly application of organic compost around the base of the tree. Pruning is also minimal, and should be completed in late wintertime or early springtime before new growth pushes out for the year. At this time, remove dead, damaged, or diseased growth as well as any crossing branches. These trees have a naturally attractive shape, and do not need additional shaping. Avoid heavy prunings, as it can cause excessive sap bleeding.
Propagation
Cladrastis 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 Yellowood tree, follow the instructions below:
Propagating Cladrastis by Cutting
Propagating Cladrastis by Seed
Propagating Cladrastis 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 late 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 to 8 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 Cladrastis 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 fall. Seeds are contained inside of the pods that dangle from branches after flowers have faded. These trees are hermaphroditic, meaning that flowers have both male and female parts. They are insect pollinated. Pods are ready to be harvested when they begin to fall from the tree naturally; there are about 4 to 6 seeds within each pod. Remove seeds from the pods and place them in a bowl of lukewarm water for 24 hours to soften the seed coat.
- Seeds can be sown in spring or fall. 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.
Cladrastis seeds are contained inside of thin-walled pods that emerge after flowers have faded.
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Cladrastis seeds are typically greenish-brown and shiny.
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Problems and Pests
Cladrastis trees are generally resistant to most pests and diseases, though they can occasionally suffer from:
- Leaf Spot
- Verticillium Wilt
- Canker
- Scale
- Aphids
- Caterpillars
Gallery
These trees produce intensely fragrant white flowers that bloom every two to three years.
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These trees look great in a wide variety of landscapes.
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Cladrastis trees have beautiful fall foliage.
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Videos
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Learn about these fantastic trees.
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How to identify these beautiful trees.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 251, Cladrastis kentukea
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