Yellowwood (Cladrastis kentukea)

Overview

The Yellowwood (Cladrastis kentukea) is a highly admired, medium-sized deciduous tree native to North America, valued by landscape designers for its graceful form and seasonal interest. Gardeners prize this species for its spectacular display of fragrant, wisteria-like white flowers that cascade from the branches in late spring. Beyond the bloom, Cladrastis kentukea offers rich green summer foliage that transforms into clear yellow tones in autumn, providing excellent multi-season appeal.

This tree features a broad, rounded crown supported by upright branching, making it an excellent specimen for providing filtered shade on residential properties. Despite its elegant appearance, Cladrastis kentukea is remarkably hardy and carries a low maintenance commitment once properly established, allowing it to thrive with minimal intervention. Its distinctive qualities—fragrant flowers, good fall color, and suitability for smaller lots—make the American yellowwood a premier choice for contemporary landscape design where both beauty and resilience are required.

Fast Facts

• Plant Family: Fabaceae
• Plant Type: Tree
• Native Range: North America
• Hardiness Zones: USDA Zones 4-8
• Size at Maturity:
  • Height: 30-50 ft
  • Spread: 40-55 ft
• Bloom Time: May
• Bloom Description: White
• Sun Exposure: Full sun
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

Planting Yellowwood is best accomplished in spring or fall when temperatures are moderate. Select a site receiving full sun to maximize flower production, though some light afternoon shade can be tolerated in the hottest climates. This species thrives in average, medium-moisture soils that are well-drained, though it exhibits surprising tolerance for drier soil conditions once its root system is fully developed. Site the tree where it is protected from excessive strong winds, which can compromise its sometimes brittle branches.

Watering requirements for Cladrastis kentukea are medium; ensure consistent moisture during the first few growing seasons to help establish deep roots. Fertilization is rarely necessary for healthy specimens grown in adequate soil. The most critical aspect of long-term care involves pruning: always prune in the summer months. Cuts made during late winter or early spring when the sap is rising can cause the tree to bleed heavily, stressing the wood.

Given its potential branch fragility, inspect the canopy after heavy snow or ice accumulation and carefully remove damaged limbs. While its bloom is profuse, remember that the tree may have flowering years that are sometimes spaced 2-3 years apart, and young trees often won’t bloom until they reach 8 to 10 years old, so patience is required to enjoy the characteristic flower display.

Landscape Uses

The Yellowwood serves beautifully as a focal point specimen due to its attractive form and seasonal color shifts. It is frequently recommended as an excellent small tree for residential lawns, perfect for placement on smaller properties where large shade trees would overwhelm the space. Its presence near patios and terraces allows observers to fully appreciate the intensely fragrant blooms in spring.

On larger properties, Cladrastis kentukea can be effectively grouped, creating a stunning drift of white fragrance. One major advantage for integrating this tree into tight spaces is its deep root system, which allows other groundcovers or smaller shrubs to be planted underneath without intense root competition. Use it as a transitional tree between manicured beds and less structured areas, capitalizing on its natural, broad shape.

Standout Features

Flower Qualities

• Showy
• Fragrant

Noteworthy Characteristics

Cladrastis kentukea, commonly called American yellowwood, is a medium-sized, deciduous tree of the legume family that typically grows 30-50’ tall with upright branching and a broad, rounded crown. It is noted for its pinnately compound foliage, panicles of fragrant white spring flowers, autumn seed pods and yellow fall color. The wood of this tree contains a yellow dye that distinctively colors the heartwood and gives rise to the common name of yellowwood.

Potential Problems

Verticillium wilt is a potential concern for Cladrastis kentukea. To prevent excessive sap bleeding, avoid pruning during late winter or early spring; summer pruning is strongly recommended. The bark is thin and susceptible to damage from sun scald, so consider planting in a location that provides some afternoon protection or applying a tree wrap in winter. Be aware that late spring frosts can damage developing flower buds, resulting in a year without blooms, and annual profuse flowering is not always guaranteed.

Frequently Asked Questions

What hardiness zones is Yellowwood suitable for?

The Yellowwood (Cladrastis kentukea) is reliably hardy in USDA Zones 4 through 8.

How large does Yellowwood grow?

This tree reaches mature heights between 30 to 50 feet tall, with a spread that typically ranges from 40 to 55 feet wide.

When does Cladrastis kentukea bloom?

Cladrastis kentukea produces its showy display of white flowers in May.

What sun exposure does Yellowwood need?

For optimal health and flowering, the Yellowwood requires full sun exposure in the landscape.

Conclusion

The Yellowwood (Cladrastis kentukea) offers exceptional value to the home gardener, blending low maintenance needs with spectacular seasonal interest provided by its abundant white flowers and brilliant yellow fall color. By respecting its specific pruning window and ensuring adequate drainage, you can cultivate this elegant specimen for decades. Check your local climate to confirm compatibility within USDA Zones 4-8 before planning the placement of your new Cladrastis kentukea.

Design Ideas

When incorporating the Yellowwood into a property, consider its mature spread; a 40- to 55-foot diameter requires significant space, making it ideal as a central feature in a large lawn area where its broad crown can be appreciated from all sides. Because its roots tend to grow deeply, it maintains compatibility with underplanting, unlike many surface-rooting shade trees. Plant it near open seating areas or low walls to capture the powerful fragrance of its spring blossoms.

Pairing this tree with contrasting foliage textures can enhance its visual impact. Consider siting it near evergreens or plants with dark green, fine-textured leaves, such as certain cultivars of Japanese Maple or needle evergreens, to make the white flowers and bright fall foliage truly pop. Avoid overcrowding, as good air circulation is important for reducing the risk of fungal issues and allowing the canopy to develop its signature rounded habit fully.

Companion Planting

Given that the Yellowwood prefers well-drained soil and full sun, companion plants should share similar low-to-medium water needs. Hostas and Astilbes are less suitable unless the tree is planted in a slightly more protected location, as they crave deep, consistent moisture that might be hard to maintain under a developing shade canopy. Instead, focus on drought-tolerant perennials that establish well once the Cladrastis kentukea has matured, such as Coneflowers (Echinacea), Black-eyed Susans (Rudbeckia), or hardy ornamental grasses.

For an excellent understory planting, consider shrubs that do not grow too tall and compete for sunlight, such as low-growing varieties of Kentucky Coffeetree (Gymnocladus dioicus), or various spreading Euonymus species for evergreen groundcover beneath the yellow fall display. The deep roots allow for ground stabilization, meaning you can effectively manage slope on your property while showcasing the Yellowwood as the dominant vertical element.