The Dragon Aster, often sold as Aster ‘Dragon’ or Dragon™ Blue Aster, is a robust perennial cultivar typically derived from the native New England Aster (Symphyotrichum novae-angliae). This plant is prized by gardeners for its reliable, late-season bloom, which provides color when most other garden plants are fading. The Dragon Aster produces abundant, daisy-like flowers, generally featuring deep purple-blue or reddish-purple ray petals surrounding a distinctive yellow-to-orange central disk. Its long-lasting flowers serve as an important late-season nectar and pollen source, making it a valuable addition for attracting bees, butterflies, and other pollinators. Successful cultivation relies on providing the proper growing environment and implementing seasonal maintenance techniques to manage its vigorous growth habit.
Essential Environmental Needs (Sunlight and Soil)
Dragon Asters thrive best when planted in a location that receives full sun exposure, meaning the plants should get a minimum of six hours of direct sunlight each day. Insufficient light causes the stems to become elongated and weak, which can make the plant flop over. Reduced sunlight also limits the plant’s ability to produce the dense, prolific blooms for which this cultivar is known.
The selection of appropriate soil is equally important for the long-term health of the Dragon Aster. These perennials prefer moist, well-drained soil, often thriving in a loamy texture that retains some moisture without becoming saturated. While they can tolerate a range of soil types, including clay, proper drainage is necessary to prevent root rot. Incorporating organic material like compost prior to planting will help improve both the soil’s structure and its ability to drain effectively. New England Asters generally prefer a slightly acidic to neutral soil pH, ideally ranging between 5.8 and 7.5.
Planting and Initial Establishment
Dragon Asters can be successfully planted in the garden during spring, summer, or early fall. Planting in spring allows the root system the entire growing season to become established, while an early fall planting gives the plant time to settle before the ground freezes. When installing the plant, the hole should be dug approximately twice as wide as the root ball but only as deep as the container it came in.
Before placing the plant into the prepared hole, gently loosen or “tease” any tightly bound roots to encourage them to spread outward into the surrounding soil. The plant crown, which is the point where the stem meets the roots, should sit level with the surface of the soil once the hole is backfilled. After planting, the area must be thoroughly watered to eliminate air pockets and ensure good soil-to-root contact.
Adequate spacing is important when planting these asters, as they tend to form large, bushy clumps. Leaving sufficient distance between plants—typically two to three feet—is necessary to ensure good air circulation. This air movement helps foliage dry quickly after rain or watering, preventing the development of fungal diseases like powdery mildew. For the first few weeks after planting, consistent and deep watering is necessary to help the plant establish a strong root system.
Ongoing Seasonal Care and Maintenance
After the initial establishment period, Dragon Asters are fairly low-maintenance, but seasonal care maximizes their performance and bloom quality. During the active growing season, routine deep watering is preferred over shallow, frequent watering, as this encourages the development of deeper, more resilient roots. Although the established plants possess a degree of drought tolerance, they will perform best if the soil is kept evenly moist, especially during periods of extended dryness.
Fertilization requirements are modest, and too much nitrogen can encourage excessive, weak stem growth at the expense of flower production. If the soil is particularly poor, a single application of a balanced, slow-release fertilizer in early spring is sufficient to support healthy growth. Alternatively, amending the soil with organic compost is an effective way to enrich the soil without risking over-fertilization.
Controlling the height and promoting a fuller, sturdier habit is achieved through a technique commonly known as the “Chelsea Chop”. This involves pinching or cutting back the stems by one-third to one-half of their height in late spring or early summer, typically before mid-July. This pruning encourages lateral branching, creating a more compact plant that is less likely to flop over and often delays the bloom time slightly. Once the flowers have finished blooming in the fall, deadheading the spent flowers can prevent unwanted self-seeding.
Dragon Asters are generally robust, but they are susceptible to powdery mildew, a fungal disease that appears as a white or grayish coating on the leaves. Prevention includes ensuring good air circulation and watering the soil at the base of the plant rather than wetting the foliage. If the mildew appears, prompt action involves pruning off the affected leaves and applying a fungicide such as neem oil or a baking soda solution. For winterizing, the stems should be cut down to a few inches above the ground after the first hard frost, which prepares the plant for dormancy and helps to manage disease spread.