The Purple Dome Aster (Aster novae-angliae ‘Purple Dome’) is a compact and vibrant variety of New England Aster. Known for its rich purple flowers and bushy growth habit, this aster is a popular choice for gardens, especially in late summer and fall, when it provides a burst of color when many other plants are starting to fade. It’s easy to care for and attracts pollinators like bees and butterflies. Below is a care guide for the Purple Dome Aster to ensure it thrives in your garden.
1. Light Requirements
- Full Sun to Partial Shade: Purple Dome Asters grow best in full sun but can tolerate partial shade. For the best blooms, aim for at least 6 hours of direct sunlight per day.
- In Shaded Areas: If planted in partial shade, the plant might not bloom as profusely, but it will still grow well, albeit with fewer flowers.
2. Soil Requirements
- Well-Drained Soil: Purple Dome Asters prefer well-drained soil that’s rich in organic matter. They thrive in loamy or sandy soil.
- Soil pH: A pH range of 6.0 to 8.0 (slightly acidic to slightly alkaline) is ideal for these asters.
- Improve Drainage: If you have heavy clay soil, you can improve drainage by adding compost or well-rotted manure to the soil before planting.
3. Watering
- Moderate Watering: Purple Dome Asters like regular moisture but don’t tolerate waterlogged roots. Water the plant when the top 1-2 inches of soil feel dry.
- Deep Watering: Water deeply to encourage the roots to grow deeper into the soil. Avoid shallow watering, which can lead to weak root systems.
- In Hot Weather: During periods of extreme heat, you may need to water more frequently, but ensure the soil has good drainage to prevent standing water around the roots.
4. Temperature and Humidity
- Cooler Temperatures: Purple Dome Asters are hardy perennials that can tolerate a range of temperatures. They do best in cool to moderate climates and are hardy in USDA Zones 4-8.
- Humidity: These asters prefer moderate humidity levels. If you live in a humid climate, make sure to provide adequate air circulation to reduce the risk of fungal diseases.
5. Fertilization
- Light Fertilization: Purple Dome Asters are not heavy feeders, but a light application of a balanced, slow-release fertilizer in the spring can promote healthy growth.
- Organic Matter: You can also amend the soil with compost to provide slow-release nutrients throughout the growing season.
- Avoid Over-Fertilizing: Too much fertilizer, especially high-nitrogen fertilizers, can encourage more foliage growth at the expense of flowers.
6. Pruning and Deadheading
- Deadheading: Regularly remove faded flowers (deadhead) to encourage more blooms and prevent the plant from setting seed too early. Deadheading will also help maintain the plant’s appearance.
- Cut Back After Blooming: Once the flowering season is over, cut the plant back to about 6 inches above the ground to maintain a tidy appearance.
- Pinching: Pinch back the plant early in the growing season (late spring) to encourage a bushier, more compact growth habit. This will also promote more flowers.
7. Winter Care
- Cold Hardy: Purple Dome Asters are hardy and can tolerate cold winters, especially in USDA zones 4-8.
- Mulch for Winter Protection: Apply a layer of mulch (such as shredded leaves or bark) around the base of the plant in late fall. This helps protect the roots from freezing and provides insulation.
- Cut Back in Spring: In the spring, you can cut back any dead stems or foliage that were left over from the winter. This will help the plant grow fresh, new shoots.
8. Pests and Disease Control
- Common Pests: Purple Dome Asters are generally resistant to pests, but they may occasionally attract aphids, spider mites, or Japanese beetles. Use insecticidal soap or a strong stream of water to remove pests.
- Powdery Mildew: This is a common issue for asters, especially in humid conditions. To prevent powdery mildew, ensure the plant has good air circulation and avoid overhead watering. If mildew appears, remove affected leaves and treat with fungicide.
- Leaf Spot and Rust: Keep an eye out for fungal diseases such as leaf spot or rust. These can be treated with fungicides or by removing and discarding infected leaves.
9. Propagation
- By Division: The easiest way to propagate Purple Dome Asters is by dividing the plant. In early spring or fall, dig up the plant and divide it into smaller sections. Each section should have roots and stems to replant in a new location.
- From Cuttings: You can also propagate by taking softwood cuttings in early summer and rooting them in moist, well-draining soil.
10. Companion Plants
Purple Dome Asters are great for pairing with other late-blooming plants, especially those that thrive in similar conditions. Some good companion plants include:
- Black-eyed Susans (Rudbeckia): Their yellow flowers contrast beautifully with the purple asters.
- Goldenrods (Solidago): These plants provide additional yellow blooms that complement the purple flowers.
- Coreopsis: Known for their bright, daisy-like flowers, these plants pair well with asters for a vibrant garden display.
Summary
The Purple Dome Aster is an easy-to-grow perennial that offers stunning purple blooms in the late summer and fall. Here are the key points to remember for its care:
- Sunlight: Full sun to partial shade.
- Water: Regular watering, allowing the soil to dry between waterings.
- Soil: Well-drained, fertile soil with a slightly acidic to neutral pH.
- Fertilizer: Light feeding in spring with a balanced fertilizer.
- Pruning: Deadhead regularly and cut back in late fall or early spring.
- Winter Care: Mulch in fall to protect the roots over winter.
By following these simple care instructions, you can enjoy the vibrant purple flowers of your Purple Dome Aster year after year.