As an educator, gardener, or parent, it’s easy to associate September with pangs of nostalgia for the abundance and freedom of summer. August ends, school begins. We head to the store to buy new pencils — and while we’re at it, some outdoor decor, because the growing season’s not done yet. We grab a couple pots of hardy mums, hoping they’ll look nice in back-to-school pictures beside a pumpkin, only to fast-forward to plants that gave up the ghost by Halloween.
They say the antidote to nostalgia is to be in the moment. My good news is that right now, summer’s last show is in the works, and it comes in the form of the “native mum,” also known as the Aster family. Like the hardy garden mum, Asters are photoperiodic — that is, triggered by the shortening days to bloom.
How does this plant beautify the late summer/early fall landscape, and how can we rescue “traditional” mums from certain death?
Mums: What’s the Word?
Chrysanthemums, (Dendranthema spp.), are sold everywhere from big-box stores to garden centers starting the second week of August until November. They originated in East Asia and Europe and are sterile, meaning that they offer no food to pollinating insects and cannot produce seed. For these reasons, I’d recommend including mums as well as other types of fall-flowering plants. Late summer and early fall are crucial times when pollen and nectar production slow down, but numbers of flying insects are still in need of fuel to migrate, reproduce, or furnish winter stores.
There’s a small space in my heart for the garden mum, about as big as what might fit between two seasonal gourds. It’s not that I don’t appreciate their wide range of color, their robust habit, or even their ubiquity; it’s that I have a hard time spending money on something I historically haven’t been able to keep alive. Let this be the year that I fill that void and learn how to take care of them!
Keeping Mum(s)
Here are some pointers if you’d like to try along with me. A note: planting in spring may be more successful as the intense blooming mums perform in the autumn means little energy is available to establish roots. In this case, give potted mums a sheltered rest in an unheated garage or shed for the winter season. If planting in fall, get them in the ground no later than mid-October.
- Choose your plants optimally: tight buds now mean more blooms later. Pick plants that are uniformly green and avoid over- or underwatered soil.
- Once home, keep your potted mums watered for the blooming season, about an inch a week, and dead-headed (meaning that spent blooms are removed periodically). Cover mums in case of hard frost and proceed to store them once the majority of blooms are spent in the late fall.
- In late fall or early winter, place lightly watered potted mums in an unheated garage. Maintain this scarce water content until early spring.
- In late March or early April, plant the root ball just at soil level, and mulch.
- Pinch summer growth until the end of July, then leave to bud for the fall season.
- Enjoy your fall-blooming mum in its low-care inground home!
- After the first frosts, add dead leaves or wood chips so that mums are under 4-6 inches of mulch for their first winter.
Asters: the Stars of September’s Garden
It’s my hope that by the end of this article, even if you don’t consider Asters to be an acceptable substitute for the mum, you’ll want both. Why Asters? For one, there are almost a dozen native varieties to choose from, each able to thrive in different settings. Once established, they require little care and are often drought tolerant.
Even better, Asters grow all around us, and once you’ve learned a little about one, you’ll be primed to see and appreciate them in situ. I think of them as fall’s cheerleaders, ushering the end of one season into the next. And unlike sterile mums, the seedheads of Asters provide winter forage for a host of songbirds — another reason to minimize your fall clean-up and feed wildlife in the process.
‘Garden Aster’/New York Aster
In visiting local big-box stores recently, I was glad to see this “nativar” of Symphyotricum novi-belgii. A “nativar” is a native plant that has been cultivated through human intervention for certain traits, like double blooms or a difference in size. While these traits may make the plant more marketable to humans, the animals relying on them may not derive as much nutritional value from this changed version. In fact, the only native cultivar of this species I saw being visited by bees was this white version, which features a more recognizable “face” to the pollinators who need to make the most of this time of year.
New England Aster
The New England Aster (Symphyotrichum novae angliae) is a standout for its vibrant purple to fuschia blooms and its height (between four and six feet). It grows well in meadow settings or light shade and in dry to moist conditions.
Aromatic Aster
A late bloomer that carries striking lilac color deep into the fall, Symphyotricum oblongifolium forms dense, shrub-like clouds one to three feet tall. While its blooms are scentless, when Aromatic Aster’s leaves are crushed, a piney scent emerges. This Aster spreads aggressively through rhizomes and seeds, making it a better choice for settings where it can sprawl.
Calico Aster
Clouds of tiny white-petaled blooms adorn multiple side branches of Symphyotrichum laterifolium. This Aster features the ability to alert pollinators to the micro-flower’s status: pinkish-mauve centers indicate they’ve been pollinated, whereas “virgin” blooms are yellow. The variation in color gives this Aster its name.
White Wood Aster
My childhood favorite fall flower, White Wood Asters are so named because of their ability to carpet forest floors in spare white-to-lavender blooms between half a foot and two feet tall. They can also be identified by serrate lance-shaped leaves and a twiggy, easily broken stem. Eurybia varicata will also display reddish centers when pollinated and yellow centers when unvisited.
Smooth Blue
Symphyotricum laeve is a two- to four-foot tall member of the Aster family with light lavender blooms and lance-shaped leaves that are smooth on top and rough underneath. This Aster spreads aggressively by seed, making it more ideal for meadow settings.
Other Care Tips for Asters
To promote blooms and tame an Aster’s tendency to flop, cut it down one-half to two-thirds of its height in June, a practice also known as the “Chelsea chop.”
Like many natives, Asters can fall prey to powdery mildew, a nonlethal but unattractive whitish fungal film. Ensuring good airflow through pruning and planting in moderate sun should help outpace this problem.
As noted above, many Asters are prolific spreaders through seed. To curb the spread, pinch spent blooms in the fall, and consider gifting the seed to a fellow gardener!
This September, manufacture your own cure for end-of-summer blues by filling your garden with these hardy fall flowers that will benefit you — and the wildlife in your yard — for years to come.
Have fall clean-up questions for Lucy? Wondering what seeds to save in the coming months? Email her at [email protected]!
Local Garden Events: Check out a range of native plants for sale at Hilltop Hanover’s Fall Native Plant Sale on Saturday, September 13, from 10 am to 4 pm.
