Asters are now one my one of my favorite fall-blooming perennials. And I kind of fell into this one by accident. When I decided to focus on perennials and pollinators for the first year of our new home’s back garden, my strategy was kind of shooting in the dark.
I went to a local nursery that has all of their perennials labeled by light needs, if they are good pollinators, their size, by when they bloom, and by if they make good cut flowers.
I chose aster because the little purple-blue flowers were lovely. But mostly because the variety I got—aster oblongifolius “Raydons Favorite,” aka aromatic aster–grows to be about 3 feet tall and wide. It makes a lovely anchor piece in the garden! And a fantastic late-season bloomer for pollinators to enjoy when everything else is dying.
Asters 101
Aster is actually the name for a genus of around 170 species of perennial flowers that grow as perennials in U.S. grow zones 3, 4, 5, 6, 7, 8, and 9. Different types of aster plants produce blue, purple, periwinkle, red, pink, and white star-shaped flowers. All have a rather delicate look to them with small petals and yellow centers.
Since they are perennial in most U.S. grow zones, that means they come back year after year. I’m in zone 7, and I planted a tiny aster in early spring right after we moved in. It absolutely exploded in size through the summer. I didn’t do any pruning, but I did stake the plant to help it grow straight.
The next year, it came back without any issues. You’ll just need to trim down all of last year’s dead foliage in the early spring. I like to let my dead foliage rest for the winter because it can be a great home for bugs!
Growth rate
In my experience, aster grows quite quickly. Specifically, my “Raydons Favorite” variety grew like an absolute weed. After planting, it grew to be about 6 times the size of when I planted it in one growing season.
The first photo below gives you a look at the size when I planted it…and then the second photo is just a few months later. It got rather large its first year, but you know what they say about perennials—the first year they sleep, the second year they creep, and the third year they leap!
That means that the first year they are focusing on developing their root systems, the second year they spread a bit more, and the third year they really start to reach their full potential.
Bloom timing
Aster blooms can begin to appear in the late summer or early fall (depending on the variety). While mine throw out the occasional bloom during the summer, they usually explode with growth in October.
Even after some light frosts, the blooms still look amazing. It’s such a welcome addition to a fall garden where everything else is dying—and a great late-season pollinator-friendly plant, too! The flowers are so cute, too. They look great in fall arrangements.
On the left below is an arrangement I made for a friend’s mom with the very last of my zinnias, some aster, and a few other things. Well, I was a week early for the party because I got the date wrong (lol), so the arrangement on the left is the one I made her the following week!
Pruning & deadheading
You probably won’t need to prune your plant the first year you plant it. Depending on how well it is getting established, you may choose to prune it back a bit during its second year in early summer. Doing so will force a more compact growth habit.
The third year I had my asters was the year I really needed to start pruning. Without pruning, the stems were getting too long and droopy. So a good pruning in early summer—about one-third of the plant—is the best way to go.
You don’t need to deadhead aster flowers after they bloom since they bloom at the end of the growing season. When the flowers and foliage die off, I recommend letting the plant rest for the winter. I generally try to wait until early spring to cut back the previous year’s perennials. Have a look below at one of my asters in March one year.
Pollinator benefits
In addition to being pretty, aster flowers are also food for a bunch of Lepidoptera species (an order of insects that includes butterflies and moths). And they bloom in a time when there aren’t many other pollinators blooming, so they make a lovely late-season snack.
That’s one of the biggest reasons I recommend aster to those looking to develop a pollinator friendly garden. We often forget about late-season blooms when planning things out, and aster is a perfect plant to fill that void!
Planting tips
If you’re looking for the best place to grow aster plants, shoot for full sun. I have mine in some of the sunniest spots in the garden. However, the plant can also tolerate part shade. It may bloom less prolifically, though.
When I planted my aster plants, I dug a hole about twice the size of the plant’s root ball. Then I put in a shallow layer of leaf compost and set the plant in. I backfilled the plant using a mixture of the dirt I dug out and leaf compost.
The leaf compost helps to lighten up the soil, making it a bit more well-draining. It also improves the overall quality and adds nutrients. Our soil sucks.
Whenever I plant a new perennial, I keep it watered regularly for the first growing season. After that, I let mother nature take care of everything. Perennials have deeper root systems once they are established, meaning they need far less care.
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Brittany is a seasoned DIY home and garden expert, running a creative brand since 2014 that inspires others with approachable plant care guides, woodworking tutorials, and decor projects. She is a certified project manager and has completed extensive coursework in the art and science of growing your own plants. Her work has been recognized by major publications, and she routinely collaborates with fellow DIY industry leaders—but her favorite thing to do is inspire you! Learn more about her here.
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