September is a bittersweet time in the garden. While many plants still look lush and lovely, others have faded to straggly echoes of their midsummer glory. And we all know what’s soon to come — the bleak garden wasteland of a Minnesota winter.
Most northern gardeners view planting as a spring ritual, with the exception of spring-blooming bulbs and cool-season veggies. But there are many other plants that do well, sometimes even better, when planted in the fall — with the bonus that you can enjoy their beauty right now.
“We recommend fall planting,” said Mary Meyer, professor and Extension horticulturist for the University of Minnesota. “Weed seed germination is less in fall so there’s not as much competition.”
Trees and shrubs, in particular, are good candidates for September planting because they establish their root systems in the fall. Rainfall is usually good, and soil temperatures remain warm.
“It’s physically easier on the plant,” said Ryan McEnany, spokesman for Bailey Nurseries. “It’s not too hot or too cold, so there’s less stress, and the plant has more time to establish itself.”
Blooming shrubs are more likely to reward you next growing season if you plant them in September rather than waiting until spring, he added. “Get them established. You’ll get to enjoy them next spring if you plant now. If you plant in spring, you may not.”
Another benefit of fall planting is that you can clearly spot the holes in your landscape and better assess which new plants could complement what’s already there, said Karen Bachman Thull, director of marketing for Bachman’s. “You can see the areas in your yard that need help.”
Planting in spring is more of a guessing game, McEnany added. “In spring, we plant not thinking about the other plants and how big they really get.” In fall, when nearby plants are mature, it’s easier to figure out which new plants will work best and where they should be placed. “You can see what else is happening,” he said.
You’ll also find more enticing prices than in spring, when gardeners are stampeding to garden centers; most annuals are now on clearance, and many perennials are discounted. “It’s really a great time, as a consumer, to add to the landscape,” Bachman Thull said.
But don’t wait too long. While September planting is optimal, you’re pushing your luck if you put it off into October. “Fall planting is good as long as there’s a month of growing season left,” said Meyer. “Through September is good.” After that, it gets iffy. Minnesota’s fall weather has been mild in recent years, but there’s no guarantee that will continue.
1. Site selection is critical. Before you plant, learn what growing conditions a particular plant needs and be sure you put it in a spot that provides that. “For flowering plants, if they need full sun, find a spot in the sun,” said McEnany. Bailey’s popular Endless Summer hydrangeas, for example, require sun to produce blooms, and perform best when they get full morning sun with dappled shade in the afternoon.
2. Keep digging. “The hole is very important, just as important as the tree,” said Bachman Thull. “Dig that hole twice the diameter of the root ball.”
3. Fortify your soil. “Add peat moss and compost, and mix it in as you’re planting, not just putting it on top,” advised McEnany.
4. Proper care. After you plant, add a layer of mulch to retain moisture. Then water, water, water. Even though September isn’t generally as hot as May, “You have to keep watering, just like earlier in spring,” said Bachman Thull. But don’t add fertilizer. “It will confuse the plant and throw off its clock,” said McEnany.
What to plant
Need ideas? Bachman and Thull and McEnany shared some suggestions:
For instant gratification, add a few annuals to perk up fading containers and garden beds. Bachman Thull’s fall favorites are cool-tolerant showy plants like hardy mums, ornamental kale and ornamental peppers. “They look very fresh,” she said. “In October, you can add permanent leaves, dried stems and seed pods to give it a little more seasonal flair.”
For gratification now — and next spring, McEnany suggests hardy shrub roses, such as Easy Elegance. Consider Screaming Neon Red, a 2015 introduction with vivid blooms and disease-resistant dark green foliage, or Coral Cove, with coral pink and yellow blooms. Both are compact and work well in smaller gardens as well as large ones.
Hardy hydrangeas also offer color now and next growing season. McEnany is big on BloomStruck, a prolific bloomer with red stems and bold red or purple blooms that turn burgundy in fall.
Shrubs with fall interest include serviceberry, especially Autumn Brilliance, suggested Bachman Thull. “In spring, it has a showy white flower. In fall, brick red foliage.” Or pagoda dogwood. “It’s a great fall shrub. The leaves turn a deep purple.” Chokeberry is another of her favorites. Its glossy leaves turn red in late summer through fall. “And the birds will snack on the berries in winter,” she said.
If you like barberry, consider one of the newer variegated varieties, such as Limoncello (chartreuse leaves edged with red) or Toscana (red leaves edged with yellow), suggested McEnany.
He also likes Sapphire Surf bluebeard. “It’s only marginally hardy [to Zone 5], but the blue color pops against reds and yellows and is good for fall,” he said. If you don’t want to risk it in the ground, consider planting it in large containers to enjoy now, then bring the containers into the garage or unheated basement for winter.
Ornamental and native grasses are other great autumn planting choices. They’ll add texture and fall interest to your landscape right away — and give you something to look at during the snowy months ahead.
“The grasses I work with are very showy in fall, and you can see what they look like — their flowers, their full height,” said Meyer. “You see them at their peak, and see what you’re getting.”