Although each plant's needs may vary and some will be more winter-hardy than others, in general about a month before the last fall frost is sufficient in giving the plant enough time to establish itself and take root.
"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.
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.
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.
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.
The best times for planting perennial flowers are during the spring and fall. Planting during these seasons will ensure your plants grow healthy and strong. In the spring, you have warmer soil, plenty of rainfall, and longer days with more sunlight. Planting in the fall also has its advantages.
For starters, spring-blooming bulbs should be planted in fall. Trust us: You'll be glad you planned ahead when you see them pop up after a long, dark winter! Get them in the ground any time before the ground freezes, which is from October to mid-December, depending on where you live.
Plant Flowers and Vegetables
If you live in a frost-free region, October is a great time to plant cool-weather flowers and vegetables in your garden. Crops such as kale, cabbage, collards, lettuce, carrots, mustard, onions, Brussels sprouts, cauliflower, beets, and garlic can all be planted in early to late October.
Spring-blooming perennials, especially in the bare root form, are best planted early in the fall. Planting in the fall while the soil is still warm will give the roots enough time establish properly. This allows the plants to emerge from well established roots, with a stronger start, the following spring. 4.
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.
Early spring and fall care are best times for transplanting. Then the weather is cooler and the plants are not using as much water. “However, don't move or transplant perennials while they are in bloom,” he says. “As a general rule, wait a few weeks after they bloom before moving.
The best time to plant any plant is during the dormant season – in North America, this is usually late fall through early spring. While it's okay to plant during the rest of the year, it will require more maintenance from you in the form of watering, fertilizers, etc.
Fall is a great time to plant another crop of spring greens such as spinach, leaf lettuce, arugula, mustard greens, and mâche because they require cooler soil for seed germination and they mature quickly.
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.
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.
However, there are cultivated plants which are more susceptible to problems if the old foliage and dying stems are left to rot. Diseases can overwinter in dead foliage, as can slugs and other pests. Old stems can also get battered about by fall and winter winds, which will damage the plant's crown and roots.
Christmas Rose. This evergreen perennial blooms from winter to early spring depending on the selection and where you live (mostly early winter in warmer regions, and as late as February or March where it's very cold).
Winter pansies are cold weather all-stars. These cheery winter blooming flowers can freeze solid and emerge from that state ready to grow and flower. Other bedding plant flowers that grow in winter include nemesia, snapdragon, sweet alyssum and flowering stock.