Want a burst of color just when the summer garden starts to fade? Powder Puff asters bloom in late summer and early fall with big, fluffy flowers in pink, purple, white and red. They're one of the best cut flowers you can grow from seed. In this guide, you'll learn when to sow asters, how to care for them, and how to keep them healthy year after year.
What kind of aster is Powder Puff?
Powder Puff is a China aster (Callistephus chinensis), an annual grown from seed each year. It's different from the perennial New England and New York asters you might see in fall borders. China asters grow about 2 to 3 feet tall, with long, strong stems topped by fully double, pom-pom-like blooms about 2 to 3 inches across.
When should you plant aster seeds?
- Start indoors: For the earliest blooms, sow seeds indoors about 6 to 8 weeks before your last spring frost.
- Direct sow: Or sow outdoors after your last frost, once the soil has warmed.
- Stagger it: Asters bloom over a few weeks rather than all summer, so sow a second batch 2 to 3 weeks after the first for a longer show.
Here in Minnesota, zone 5a, starting asters indoors in late March or early April gets them blooming by late summer.
How to sow aster seeds
- Sow shallow. Plant seeds about 1/8 inch deep in seed-starting mix.
- Keep warm and moist. Seeds usually germinate in 7 to 14 days at about 65 to 75°F.
- Give them light. Grow seedlings under lights or in a very sunny window to keep them stocky.
- Harden off. Gradually get seedlings used to outdoor conditions over about a week before transplanting.
- Space them out. Plant about 9 to 12 inches apart for good airflow.
Caring for asters
- Sun: Full sun gives the strongest stems and most flowers.
- Soil: Rich, well-drained soil with some compost mixed in.
- Water: Keep soil evenly moist, about an inch a week. Water at the base of plants to keep leaves dry.
- Mulch: China asters have shallow roots, so a layer of mulch helps keep them cool and moist.
- Support: Tall plants can flop in wind or rain. Stake them or run a row of netting about a foot above the soil.
How do you keep asters healthy?
China asters can be bothered by aster wilt and aster yellows, diseases that build up in the soil or are spread by leafhoppers. A few simple habits help a lot:
- Rotate: Plant asters in a different spot each year rather than the same bed.
- Remove sick plants: Pull any plants with yellowing, distorted growth or green, misshapen flowers, and don't compost them.
- Space well: Good airflow keeps leaves dry and healthy.
Cutting asters for bouquets
Powder Puff asters are a florist's favorite for good reason. Cut stems when the flowers are about one-third to half open, early in the morning. Strip the lower leaves and put them straight into water. They often last a week or more in a vase.
Flowers to grow alongside asters
- Powder Puff Aster Mix (about 100 to 120 days to bloom): a colorful mix of fully double flowers on long stems.
- Velvet Queen Sunflower: deep red-brown blooms that look great in late-summer bouquets with asters.
- Purple Coneflower: a hardy perennial that blooms around the same time and feeds pollinators.
Plan for late-summer color
A few sowings of asters will keep your garden and your kitchen table bright as summer winds down. Start some seeds this spring and enjoy the show. All our seeds are non-GMO and USA grown, and I pack them by hand here in Minnesota.
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