"Fall is an excellent time to plant almost any perennial, with the exception of many ornamental grasses, which are better planted in spring," says Erin Schanen, Troy-Bilt's gardening partner, a master gardener volunteer and creator of The Impatient Gardener blog and YouTube channel.
Mid-August to mid-October is an ideal time of year to plant new trees, though, that time frame can be stretched into November and December. To be 100% sure, measure soil temperature early in the morning for a few, consecutive days. If your soil is consistently 50° F or higher, you're good to plant.
You can transplant perennials anytime until the ground freezes in the fall, or wait to transplant them in the spring. Fall is an excellent time to transplant herbaceous perennials because your plants will then have three seasons to establish a good root system before hot summer weather sets in next year.
October is the season to plant spring-blooming bulbs, wildflowers, and many standard gardening favorites. The flowers that don't blossom this winter can spend the cold season in the ground, strengthening their root systems in preparation for a springtime bloom.
Violas and Pansies
These hardy little flowers not only have gorgeous blooms but can survive almost anything winter has to dish out. Violas and pansies grow best in partial shade but need a minimum of four hours of sunlight a day.
September is the best month to divide and transplant perennials, but you can still be successful in early October. This is a good time to see the plants that are not healthy and to assess your garden design.
And some of the annuals that are normally considered spring flowers will flourish in the cooler fall weather, if only for a short time. Mums, specifically florists' or garden mums, have become the go-to plants for a fall garden.
The newly emerged growth of most perennials can tolerate temperatures in the low 30s and upper 20s Fahrenheit. Freeze damage may occur if temperatures drop into the lower 20s or teens. Most well-established perennials that have been damaged by freezing temperatures should survive.
Autumn is a great season for annuals, low-maintenance perennials and evergreen shrubs to shine. In fact, some of the most popular flowers, like colorful mums, roses, dahlias, purple pansies and yes, even bright yellow sunflowers, all bloom around September and October.
Perennial Flowers: Most perennial plants do not suffer frost damage and do not need to be covered. Frost sensitive perennials include Hostas and Bleeding Hearts. They should be covered to protect their foliage and flowers. Cover any blooming or budded up perennials.
Look for deals on spring-blooming bulbs, perennials, trees, and shrubs, which can all be planted in the fall, up until your area gets hit with a hard frost. And don't forget your lawn; cool-season turfgrass can be seeded this time of year, too.
There are a few bulbs that are winter blooming flowers. Dainty and delicate, snowdrops (Galanthus) are true spring harbingers. No bigger than a dandelion, they bravely push through snow and even ice to grace the garden with their dangling white bell blooms.
Planting. Most perennials should be planted in the fall or early spring. Fall planting gives the plant more time to become established before the start of active growth in the spring. Fall-planted perennials are usually well-established before hot weather.
It's common to think that everything should be chopped down to the ground in the fall, but some perennials actually need their foliage to protect new shoots through the winter. Other varieties offer up important habitat for local wildlife and some perennials provide height and interest through the winter months.
Some Hardy Perennials Need Winter Protection in the North and Midwest, and Tender Perennials Require Special Protection Methods. Many perennials hardy for your zone make it through winter just fine with no special attention.
Some perennials, like hostas, peonies and daylilies, need to be pruned in fall to avoid winter damage. Plants like these should be pruned after the first few frosts in late fall or early winter. Other perennials like mums and coneflowers are better off being pruned in spring just before new growth comes in.
Think about ways to add color and draw beneficial insects to your fall gardens. Consider planting nasturtiums, marigolds, asters, cosmos, mums, and anemones. Plan out your fall pots and planters. Summer blooms are fading, but there are many opportunities to add color and visual interest to your landscape.
Mid- to late-August is often an excellent time to plant fall flowers, as long as the weather isn't still so hot that the plants will suffer heat stress. But don't wait too late to plant, or you'll have a very short window to enjoy your flowers. Check the growing requirements for each plant.