Purple cestrum (Cestrum elegans)
Purple cestrum (Cestrum elegans) is a fast-growing, showy shrub blooming May-Sept with red-violet tubular flowers. Hardy in Zones 8-11.
Complete Plant Information
Overview
The Cestrum elegans, commonly known as Purple cestrum, is a vigorous, climbing shrub native to southern Mexico, offering striking tropical flair where hardy. Its chief appeal lies in its nearly continuous display of rich, red to violet tubular flowers, which are especially attractive to hummingbirds. While prized for its color, gardeners should be aware of its fast growth rate, which necessitates regular management to keep this plant contained in smaller spaces.
This deciduous shrub thrives in conditions ranging from full sun to partial shade and prefers average, well-draining soils. It handles dry spells reasonably well once established but performs best with consistent moisture during peak heat. The mature size of Cestrum elegans can reach significant proportions, often spanning 6 to 10 feet in both height and spread, confirming its role as a bold specimen or screen.
For gardeners in cooler climates, Purple cestrum serves admirably as a fast-growing annual, injecting immediate, lush, and flowering interest into summer borders or bird-friendly gardens. Where it is perennial (Zones 8-11), managing its arching stems through heavy pruning becomes crucial for maintaining desired structure.
Fast Facts
- Plant Family: Solanaceae
- Plant Type: Deciduous shrub
- Native Range: Mexico
- Hardiness Zones: USDA Zones 8-11
- Size at Maturity:
- Height: 6-10 ft
- Spread: 6-10 ft
- Bloom Time: May to September
- Bloom Description: Red to violet
- Sun Exposure: Full sun to part shade
- Water Needs: Dry to medium
- Maintenance Level: Medium
How to Grow
Planting your Cestrum elegans should occur in spring after the threat of frost has passed, ensuring robust establishment before the summer heat. It requires fertile, well-draining soil. If your soil is heavy clay, incorporate ample organic matter to improve aeration, as good drainage is paramount for this species.
During the growing season, supplement the medium water needs with regular irrigation, especially during hot, dry weather, to maximize bloom production. While Purple cestrum tolerates occasional dry soil, consistent moisture coupled with regular feeding during periods of active growth will encourage the best performance from this fast-growing shrub.
Maintenance for Cestrum elegans centers heavily on pruning. In large, warm-climate settings, it can be allowed to form a dense, broad mass. However, for formal landscapes or smaller areas, heavy pruning is recommended, often cutting back stems significantly in late winter or early spring to shape the plant and control its spreading tendencies. Where not hardy, treat it simply as an annual that is replaced each spring.
Landscape Uses
Where hardy, Purple cestrum excels when provided vertical support; it can be effectively trained to climb an arbor or trellis, leveraging its natural vining habit while keeping it off garden paths. It is also specified for mixed borders needing rapid coverage or in dedicated bird gardens, as its flowers attract hummingbirds and its subsequent berries are appealing to avian visitors.
In zones outside of the 8-11 range, its vigor makes it an outstanding, season-long annual feature. Plant it alongside tropical foliage plants that share similar sun and moisture requirements to create a cohesive, exotic-looking display. Even when used as a temporary planting, the extended bloom time of Cestrum elegans offers consistent mid-season color.
Because of its aggressive nature, avoid planting Purple cestrum near sensitive natural areas, as it is known to escape cultivation where conditions are favorable. In structured beds, ensure companion plants are robust enough to compete with its fast growth, or alternatively, use it as a dramatic backdrop plant where containment is less critical.
Standout Features
Flower Qualities
- Showy
- Good Cut
Noteworthy Characteristics
Cestrum elegans, commonly called purple cestrum, is a climbing shrub-like perennial native to southern Mexico. Its arching stems are covered in fine, dense hairs, and can reach 6-10’ in height with an equal spread. The red to violet tubular flowers (1.5” long) form in terminal clusters and are attractive to hummingbirds, with blooms nearly continuous in warmer climates.
Tolerances
- Dry Soil
Potential Problems
The Purple cestrum generally enjoys a good reputation regarding pests and diseases, reporting no major issues that commonly plague ornamental shrubs. This relative resistance makes management simpler than for many other flowering perennials. Focus your gardening efforts primarily on cultural management, like ensuring proper pruning timing and soil drainage, rather than intensive pest control efforts.
Because of its rapid growth, the primary “problem” associated with Cestrum elegans is its tendency to become invasive within a managed garden space if left unchecked. If you desire a smaller footprint, be diligent with your routine heavy pruning to stimulate bushier growth and contain the size of this beautiful, flowering plant.
Frequently Asked Questions
What hardiness zones is Purple cestrum suitable for?
The Cestrum elegans is generally hardy in USDA Zones 8 through 11.
How large does Purple cestrum grow?
This shrub typically matures to a height and spread between 6 and 10 feet.
What sun exposure does Cestrum elegans need?
It performs well in locations receiving full sun to partial shade throughout the day.
When does Purple cestrum bloom?
Blooms appear throughout the season, typically from May into September, displaying red to violet coloration.
Conclusion
For reliable summer color and significant vertical accent, the Purple cestrum presents a rewarding opportunity for gardeners across warm climates. Its attractive, hummingbird-friendly blooms and established heat tolerance make Cestrum elegans a memorable addition to the landscape. Before planting, confirm your location falls within USDA Zones 8-11 or plan to treat it as a spectacular, fast-growing annual for immediate seasonal impact.
Wildlife Benefits
The tubular, nectar-rich flowers of Cestrum elegans are a magnet for nectar-feeding birds, particularly hummingbirds, throughout the long blooming season from May through September. Planting this shrub near windows or patios can provide excellent bird-watching opportunities, integrating wildlife interest directly into your outdoor living spaces. Furthermore, the subsequent red berries, while potentially toxic to humans and pets, provide a late-season food source for various bird species.
companion Planting
When incorporating Cestrum elegans into borders, pair it with plants that tolerate similar soil conditions—medium to dry moisture with good drainage—and enjoy comparable sun exposure. Consider drought-tolerant Mediterranean shrubs or perennials such as Lavender (Lavandula) or Rosemary (Salvia rosmarinus) for the foreground, as they require similarly well-drained environments. Larger, coarse-textured grasses can also complement the finer appearance of the leaves on the Purple cestrum.
