Coral tree (Erythrina × bidwillii)

Overview

The Erythrina × bidwillii, commonly known as the Coral tree, offers exceptional visual drama through its vibrant floral display, making it a valued ornamental accent in warmer temperate gardens. This hybrid plant provides substantial structure, maturing into a multi-stemmed shrub or small tree ideal for focal points where its stunning red coloration can be appreciated. Gardeners appreciate low maintenance needs combined with significant aesthetic impact throughout the growing season.

Developed from a cross between E. herbacea and E. crista-galli, this Coral tree thrives when placed in full sun conditions. It matures reliably between 8 and 12 feet tall, offering a manageable size for use as a screen or specimen planting. Its flowering season runs from early summer right up to the first hard frost, ensuring long-lasting color that is particularly attractive to local hummingbirds.

As a deciduous plant, Erythrina × bidwillii benefits from structural pruning in the spring to define its shape and maintain vigor. While it prefers evenly moist conditions, it exhibits tolerance across various well-draining soil types, provided drainage is adequate. Successful cultivation relies heavily on proper siting concerning humidity and winter protection in the colder reaches of its hardiness range.

Fast Facts

• Plant Family: Fabaceae
• Plant Type: Deciduous shrub
• Native Range: Tanzania
• Hardiness Zones: USDA Zones 8-10
• Size at Maturity:
  • Height: 8-12 ft
  • Spread: 6-10 ft
• Bloom Time: June to frost
• Bloom Description: Red
• Sun Exposure: Full sun
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

Planting the Erythrina × bidwillii should ideally occur when the risk of frost has completely passed, ensuring the plant establishes roots before the stress of summer heat sets in. Select a site receiving consistent, unimpeded full sun. While the plant prefers evenly moist, well-draining, sandy loams, it is remarkably tolerant of various soil textures, though excellent drainage is non-negotiable to prevent root issues.

Ongoing care for this Coral tree is straightforward; maintain a medium watering schedule, avoiding soggy conditions. Due to its robust nature, heavy fertilization is often unnecessary. The most critical cultural practice is pruning; cut back stems in the spring to manage the height and growth habit, especially if dieback occurred over winter. This plant is slow to emerge in spring, so patience is essential before resuming summer maintenance routines.

For gardeners positioned in the colder sections of Zones 8 or 9, winter preparation is crucial. A generous layer of mulch applied over the root zone provides necessary insulation against light frosts, which may cause top-growth dieback. Even if the entire plant freezes back to the ground, the roots of Erythrina × bidwillii should survive, producing vigorous new growth the following season, though flowering may be slightly delayed compared to frost-free locales.

Landscape Uses

The versatility of the Coral tree makes it highly adaptable in landscape design. Its mature height and airy structure lend themselves perfectly to functioning as a small Shade Tree where a broad footprint is not desired. Furthermore, it excels when used as a specimen planting, providing a colorful vertical element against simpler architectural backdrops.

For gardeners needing screening or taller boundary definition, this deciduous shrub can be planted in masses to create a dense visual barrier. Those with mild climates can capitalize on its plasticity by training the woody stems to climb or adhere to a sturdy trellis structure, transforming it into a vibrant living screen or wall accent. Due to its unique floral show, avoid placing it directly next to plants that compete visually during the peak summer months.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Erythrina × bidwillii, commonly called Coral tree or Bidwill’s hybrid coral bean, is the result of a purposeful, interspecific cross between two Erythrina species: E. Herbacea, native to the southern United States, and E. Crista-galli, native to central South America. This plant is a deciduous, multi-stemmed shrub or small tree that can reach up to 12’ tall and 10’ wide, featuring compound leaves with three deltoid leaflets. Clusters of bright red, 2” long blooms appear on terminal flowering stalks up to 3’ long, beginning in summer and continuing until frost, attracting hummingbirds rapidly.

Tolerances

Potential Problems

The Coral tree (Erythrina × bidwillii) is generally regarded as having few significant issues regarding pests or diseases, offering a low-hassle addition to the garden landscape. The primary concern arises from improper site selection related to moisture management during cold periods. Root rot poses a significant threat if the plant is situated in poorly drained soils, especially in areas experiencing cold winters where saturated ground freezes around the roots.

To mitigate this risk, always amend heavy soils heavily with grit or sand to maximize percolation before planting. If you observe dieback in colder zones, ensure that winter soil moisture remains low to moderate; avoid overhead watering late in the fall. If complete dieback occurs, prune the dead wood away cleanly in spring, allowing the insulated rootstock to resprout vigorously.

Frequently Asked Questions

What hardiness zones is Coral tree suitable for?

The Erythrina × bidwillii is reliably hardy in USDA Zones 8 through 10, though root hardiness is often cited down to 15°F (Zone 8b).

How large does Coral tree grow?

This deciduous shrub typically reaches a height between 8 and 12 feet, with a corresponding spread ranging from 6 to 10 feet at maturity.

What sun exposure does Erythrina × bidwillii need?

This Coral tree requires full sun exposure to ensure optimal growth and the longest possible bloom season extending from June to frost.

When does Erythrina × bidwillii bloom?

Flowering commences in June and continues robustly until the first significant frost, presenting brilliant red flowers.

Conclusion

The Erythrina × bidwillii stands out for its long bloom period, striking red flowers, and relatively low maintenance requirements once established in the right environment. Integrating this unique Coral tree into your landscape provides excellent vertical interest and supports local wildlife, particularly hummingbirds that are drawn to its tubular blossoms. Before planting, confirm your location falls within USDA Zones 8-10 and ensure your chosen soil offers excellent drainage to secure years of vibrant performance from this beautiful hybrid.

Companion Planting

Selecting companions for Erythrina × bidwillii should focus on plants that share a full sun requirement and thrive in well-drained conditions. Consider pairing the bright red flowers of the Coral tree with silvery foliage plants, such as various Artemisia species, to create a dynamic contrast that emphasizes the tropical feel of the blooms. Drought-tolerant perennials that bloom later in the season can serve as excellent ground covers, filling in the space beneath the canopy as the shrub matures.

For structure at eye level, consider integrating grasses or structural succulents (where climates allow) that do not compete heavily for surface moisture. Since the Coral tree can suffer top-dieback in cooler zones, companion plants should also be resilient enough to handle a light frost or be easily replaced or cut back in the spring without affecting the recovery of the Erythrina.

Wildlife Benefits

One of the most celebrated attributes of Erythrina × bidwillii is its powerful attraction to avian visitors. The deep red, substantial clusters of flowers are perfectly shaped for hummingbirds seeking nectar. Placing this plant near windows or patios in Zones 8-10 creates a natural viewing opportunity for these fast-moving birds throughout the long summer season.

Beyond hummingbirds, the genus Erythrina often provides valuable habitat and food sources. While the primary appeal is the flower nectar, gardeners should be aware that many Erythrina species produce distinct seed pods later in the year. Although specific fruit qualities are not listed, planting this Coral tree contributes significantly to garden biodiversity.