Why You Shouldn't Cut Back Aster Flowers In Late Summer (& Why It Matters So Much)

Asters are gorgeous members of the daisy family that light up the autumn landscape with their white, purple, or blue blooms, and they provide an excellent source of food for wildlife. If you cut back these fall-bloomers while pruning other perennials in late summer, you'll miss out on feeding essential pollinators like monarch butterflies. In fact, even deadheading these common flowers is a mistake if you want to encourage all sorts of wildlife to flourish in your yard at the end of the growing season.

Asters bear flowers from late summer to fall. Many asters are perennial native plants that provide food for local bees, butterflies, hummingbirds, and songbirds, and are one of the best plants to attract monarch butterflies (and brighten up your yard). New England asters (Symphyotrichum novae-angliae) are particularly effective at attracting monarchs, providing them with nectar as they embark on their yearly fall migrations. 

Indeed, some of the most important flowers for pollinators in fall are asters and sunflowers — so late summer is clearly a time when gardeners shouldn't be cutting back these plants. In the garden, asters look great with goldenrod, another late season bloomer and one of the most important fall plants for pollinators, which you shouldn't be pruning in the summer either. A few flowers at the right time and in the right place can matter so much to migrating wildlife like monarchs.

So, when is the best time to cut back asters for the best wildlife impact? Species like New England asters can be cut back directly after blooming, but you may want to avoid doing so until late spring instead, because their ecosystem services don't end when their flowers fade. Other pollinators like native bees are busy foraging from asters in late summer as well, so avoiding cutting them back at this time of year helps more than just monarchs.

Leaf litter from perennials like asters also matters to insects, providing habitat where they can spend the winter. Birds also use these plants for food, eating dried aster seeds when the seedheads are left on the plants over winter. So instead of cutting back asters once the blooms fade, wait until late spring to cut back the dried vegetation. If you're looking for additional garden tasks as fall approaches, late summer is a great time to plant new flowering perennials to grow alongside your asters, as new transplants will still have enough time to establish their root systems in late summer before cold weather arrives. Remember to add a layer of mulch to protect new plants through the cold.