Guide to Growing Calico Aster (Symphyotrichum Lateriflorum)

The calico aster is a common sight in late summer when its tiny white flowers appear like thousands of tiny stars (for which asters are named) along roadsides, near woodland edges and in meadows.

Also known as the starved aster, this herbaceous perennial has small, spiky, dark green glossy leaves and compact pale flowers with bright rosy pink centers, making it a very distinctive wild aster. It blooms from late summer into autumn. In the fall, the leaves sometimes turn a dark purple color, lending it the nickname "Lady in Black."

In Europe calico aster is a cottage garden staple, but it is somewhat resistant to being cultivated in North America; usually it reseeds itself from wild locations.

Common Name	Calico aster, starved aster
Botanical Name	Symphyotrichum lateriflorum (previously Aster lateriflorus)
Family	Asteraceae
Plant Type	Perennial
Mature Size	2-3 ft. tall
Sun Exposure	Partial shade to full sun
Soil Type	Tolerant of most well-drained soils
Soil pH	Slightly acidic to neutral
Bloom Time	Late summer
Flower Color	White petals, pink centers
Hardiness Zones	4-8 (USDA)
Native Areas	Eastern and Central North America, Europe

Calico Aster Care

It’s very easy to care for a calico aster in wild, woodland, or meadow areas. It tends to reseed itself if you want to grow them in specific areas they can be transplanted.

• Plant calico aster in a semi-shady spot with well-draining soil. Planting in a sunny location may cause it to spread too invasively.
• Water the calico aster regularly after planting until it's established, but after that, normal rainfall and/or regular garden watering should be sufficient. It may need some extra water in periods of drought.
• Calico aster needs no supplemental fertilizing.
• Divide or dig it up to keep it from spreading and going where you don’t want it to.

Soil

The calico aster is fairly tolerant of different soil types and will grow in clay soils or thin soils, but it prefers a well-drained, moderately fertile soil. Its ability to survive in hard or dry soils in shady conditions make it quite tenacious with a tendency to be invasive.

Light

Calico aster will grow in most light conditions but prefers to be in partial sun. It will grow in shady areas and does very well in partial shade conditions. Sometimes if grown in full sun, the calico aster will reseed more aggressively than in shady spots.

Water

The calico aster is fairly drought tolerant, but in prolonged periods of dry or hot weather, it may need some extra water. Water regularly in spring when new young plants appear.

Temperature and Humidity

Like other native asters, the calico aster is very cold hardy. In areas with hot summers, it does best in shady or semi-shady locations.

It needs good air circulation to avoid a tendency to get powdery mildew on its leaves in humid conditions, so if the plants start to get too crowded, thin them out.

Avoid growing in wet or swampy areas.

Fertilizer

The calico aster doesn’t need supplemental fertilizer of any kind.

Pruning

The calico aster doesn't need pruning, though some gardeners will cut it back in fall when it can be cut back all the way to the ground.

It's not a bad idea to deadhead or snip off the flowers before they go to seed to help prevent it from spreading too invasively in your garden.

Propagating Calico Aster

This native aster tends to self-propagate, meaning it self-seeds. The tiny seeds are spread by wind, foot traffic, and wildlife, like birds and rodents.

Like many native plants, it can be resistant to cultivation, but this one may be easily dug up from its wild spots and transplanted.

Transplant your calico asters in spring or fall by digging up or dividing the clumps. Choose a semi-shaded spot for the separated plants, especially if your summers tend to get hot. Water well after planting.

Common Pests and Plant Diseases

Calico aster is an extremely hardy plant. It’s not generally bothered by pests and is visited by many different insect pollinators.

It is somewhat susceptible to a few diseases: verticillium wilt and powdery mildew.

Verticillium wilt is caused by six different species of fungi found in soil. Plants affected by this disease will tend to get yellow leaves, which will then turn brown before the plant dies. There is no known treatment for it, but affected plants should be removed from your garden and thrown away (don’t put it in your garden compost).

Powdery mildew is common for calico asters and occurs when plants don't have enough air circulation, whether because they have grown too large, are crowded by other plants, or are growing too close to a wall, fence, or other structure.

Cut away any affected leaves. If the powdery mildew affects the entire plant, dig it out and dispose of it separate from your garden compost.