Planting, Growing, and Caring for Asters
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Planting
Asters prefer areas with cool, moist summers and cool nights in sites with full to partial sun. In warmer climates, asters do not like the hot midday sun. Soil should be moist but well-draining and loamy. Wet clay soil will lead to root rot, and dry sandy soil will lead to plant wilt. Mix 2 to 3 inches of compost into the soil before planting.
When to Plant Asters
- The best time to put young aster plants in the ground is in mid- to late spring after the danger of frost has passed. (See local frost dates.)
- Or, you can plant mature, potted asters when available at garden centers (typically in the late summer or early fall).
- Asters can be grown from seed, but germination can be uneven. If desired, plant seeds in the fall or start them indoors in the winter.
How to Plant Asters
- When planting young aster plants outside in the spring, space them 1 to 3 feet apart, depending on the type and how large they’re expected to get.
- Fully grown asters, such as those available in late summer or early fall, should be planted about 3 feet apart.
- If planting seeds, sow 1 inch deep in pots or flats and refrigerate them for 4 to 6 weeks to simulate winter dormancy. This cold period will kick-start germination.
- Water well, and spread mulch around the plants to keep the soil cool and prevent weeds.
Types
The most common asters available in North America are the New England aster (Symphyotrichum novae-angliae) and the New York aster (Symphyotrichum novi-belgii). Both of these plants are native to North America and are great flowers for pollinators. We recommend planting a native species of aster over a non-native species when possible, so talk with your local Cooperative Extension or garden center about which species are best suited to your area. Look for varieties with disease resistance.
North American Asters
- New England asters (S. novae-angliae): Varieties have a range of flower colors, from magenta to deep purple. They typically grow larger than New York asters, though some varieties are smaller.
- New York asters (S. novi-belgii): There are many, many varieties of New York asters available. Their flowers range from bright pink to bluish-purple and can be double, semi-double, or single.
- Blue wood aster (S. cordifolium): Bushy with small, blue-to-white flowers.
- Heath aster (S. ericoides): A low-growing ground cover (similar to creeping phlox) with small, white flowers.
- Smooth aster (S. laeve): A tall, upright aster with small, lavender flowers.
- Aromatic aster (S. oblongifolium): Multi-branched at the base, stiff upright stems, with lavender or pink flowers.
European/Eurasian Asters
- Frikart’s aster (Aster x frikartii) ‘Mönch’: Hailing from Switzerland, this mid-sized aster has large, lilac-blue flowers.
- Rhone aster (A. sedifolius) ‘Nanus’: This aster is known for its small, star-shaped, lilac-blue flowers and compact growth.
Catherine Boeckmann
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So I decided to give planting a shot and I bought Aster seeds.. I had no idea how to plant, actually I have no knowledge about planting at all .. Anyway I followed my instinct and prepared the soil, I actually mixed a 2/3 soil with 1/3 compost and watered it a little, then I picked the seeds and pushed them into it, but not so deep .. After I finished I wateredthe soil well and positioned it in a full sunny spot ..
Then I thought why I haven't google it, so I did .. And here it's, all the results are talking about 6 - 8 weeks in the refrigerator, and I just got confused ..
I need to know if my seeds are going to grow, or at least if theres anything I can do now !
P.S. I'm watering it twice a day
Hi Dana,
Do not overwater. Just keep the soil moist. Use a spray bottle so that you don’t disturb the seeds too much. We suggest that you cover the pots or trays with plastic. This will keep the soil moist so that you don’t need to water. You should see new growth after about 10 days. When the seedlings emerge remove the plastic and mist the soil lightly. Put the plants in your sunniest window. When the seedlings have their first leaves transplant into bigger individual pots.
I have a large aster plant in my new yard. It dried out and fell over this winter. Should I cut it to the ground?
Yes, you can cut off the dried out dead branches. This is normal for asters. As soon as the weather warms up you should see some new growth from the bottom of the plant.
I just bought a pot of asters a week ago and the leaves started turning brown from bottom up. At first, I watered every 2 days. When they start wilting, I asked the seller about it and he said to water everyday. So I watered every night. But it's not helping. Need help urgently. Really don't want the Asters to die. Or I at least want them to last till the Chinese New Year. Thanks in advance.
Asters grow best in full sun and in moist well-draining soil. Make sure the soil is not too wet. Please see our planting and care tips at the top of this page.
I have many aster plants that bloom beautifully. However, at one site, there's a lush, green aster with many little buds on it, but for the second year, the plant doesn't flower. It's planted in full sun, doesn't get chemical fertilizer, and is watered somewhat every few days. The soil seems to be decent loam. Why won't this little guy bloom???
If the plants foliage looks nice with no signs of insects or yellowing keep the plants moist and do not fertilize. Add some mulch around the plant to keep the soil cool and moist. Hopefully the cooler weather will produce some flowers for you.
I got a pot of aster flowers and don't know anything about them. I live in Wichita, Kansas. Can these grow inside?
We’ve never grown asters inside. We’d suggest you grow asters in a pot on your patio and bring then inside and sit on a sunny window once they bloom.
