New England asters (Symphyotrichum novae-angliae) are a standout fall flower. The plants feature erect stems that can grow several feet tall. The stems have fine “hairs,” or bristles, on them and sport many lance-shaped leaves extending from them. In the late summer to early fall, the profuse daisy-like blooms appear. The flowers are typically a pinkish-purple color with yellow-orange centers, and they have roughly a 1.5-inch diameter. Pollinators love the blooms. In northern climates, you can plant New England asters from spring to early fall, and they should become established before winter. In southern climates, it’s best to plant them only in the spring and fall, as hot summer temperatures can be damaging to a plant that isn’t yet established. Asters are fast growers and will typically bloom in their first year.
|Botanical Name||Symphyotrichum novae-angliae|
|Common Name||New England aster|
|Plant Type||Herbaceous perennial|
|Mature Size||3 to 6 feet tall and 2 to 3 feet wide|
|Sun Exposure||Full sun|
|Soil Type||Average, medium moisture, well-draining|
|Soil pH||Slightly acidic|
|Bloom Time||August to September|
|Flower Color||Pink-purple, purple, white|
|Hardiness Zones||4 to 8|
|Native Area||Eastern North America|
New England Aster Care
New England asters grow naturally in a variety of sites, including prairies, marshes, and forest edges. Under ideal conditions, they will easily spread in a garden bed and make excellent mass plantings. If you select a growing site that gets lots of sun and has rich soil, the asters’ care needs will be minimal. Your main task might simply be watering when there isn't enough rainfall and the soil dries out.
Moreover, in the first part of the summer, pinching back stems every few weeks can promote a bushier and more compact growth habit. However, stop the pinching process by August, or you might accidentally take off some flower buds. If your asters become very tall and lanky, you might need to stake them to prevent the stems from flopping over. Then, cut the asters to the ground after they're done flowering and the foliage dies in the fall. This prepares your garden bed for new growth the following spring.
New England asters need a spot with full sun to grow and bloom their best. That means their growing site should get at least six hours of sunlight on most days.
These plants prefer rich soil with a slightly acidic soil pH and good drainage, but they can grow in other soil types as well. They’re even tolerant of clay soil.
Like many other flowers, New England asters like moist soil. They can tolerate lower levels of soil moisture as long as it’s not completely dry to the touch. Water your plants well during stretches with no rainfall.
Temperature and Humidity
New England asters tend to grow vigorously throughout the climates of their USDA hardiness zones. If you are planting seeds, they should germinate with a soil temperature of 65 to 75 degrees Fahrenheit. Extremely hot weather can make the plants wilt, but they should come back fine once the temperature cools. Humidity generally isn’t an issue, though ensure that your asters will have good air circulation when planting them. Poor air flow plus high humidity can be a breeding ground for disease on plants.
Plan to fertilize your asters in the spring when new growth appears. Use a water-soluble or granular fertilizer made for flowering plants. You also can enrich the soil with compost.
Asters are generally hardy flowers, but they can be susceptible to powdery mildew. This is a fungal disease that leaves patches of white or gray powder on the leaves and stems of an infected plant. Check the undersides of leaves, as this is where it often first appears. In addition to the white or gray patches, the plant also might yellow, look withered, and lose leaves.
To treat powdery mildew, you can apply a fungicide labeled for the disease. It’s also recommended to prune off infected portions of the plant, especially if it’s only on a small area and hasn’t spread yet. Prevention is key, as well. To avoid powdery mildew problems with your asters, make sure there is good air flow among the plants. Thin your asters by dividing them every few years in the early spring or fall. Also, always water at their bases, not from overhead.
New England Aster Varieties
There are many New England aster varieties, including:
- ‘Harrington’s Pink’: Rose pink flowers
- ‘Septemberrubin’: Purple-red flowers
- ‘Alma Potschke’: Pink flowers
- ‘Purple Dome’: Violet flowers
- ‘Barr’s Blue’: Violet-blue flowers