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.
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.
Generally speaking, spring-flowering bulbs should be planted in the fall (a few weeks before first frost), while summer-flowering bulbs should be planted in the spring (a few weeks after last frost).
Plants like chrysanthemums, nasturtiums and asters are wonderful choices for seasonal planting arrangements. While perennials that will survive the winter are great choices, autumn is also a great time to explore new ideas will short-season annuals too.
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.
Plant wallflowers, forget-me-not, Bellis, Primula, Viola (including winter pansies) and other spring bedding plants in prepared ground or pots.
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.
Gardening in the fall provides a longer period with more 'good' days, as compared to the often tumultuous spring season. Plus, if you plant in fall you'll end up ahead of the game and won't have to rush to get everything done after winter. In fact, a good strategy is to plant perennials when you plant your fall bulbs.
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.
In areas with cold winters, such as USDA Hardiness zones 5 and 6, you'll generally want to wrap up fall planting by late October, and by mid-October in zones 3 and 4. But better late than never!
If you're unsure, mid-November is a safe planting deadline for nearly everyone. - Get everything in the ground before the ground freezes. If you still have plants in their nursery pots, get them in the ground before winter, no matter how late it has gotten.
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.
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.
Grow an Edible Garden With Fall Vegetables
For a cool-weather vegetable harvest, plant lettuce, collards, carrots, Brussel sprouts, spinach, broccoli, radish, and more. The general rule of thumb is to plant fall vegetables from seed 90 days before the first frost.
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.
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).
The best month to plant flowers in spring is really down to the USDA hardiness zone you live in and the likely last frost date. This is likely to be from around March, but if you live in a northern zone, be sure to plant frost-tolerant perennials until you are happy that the risk to more tender flowers has passed.
"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.
Most flowers should be planted after your region's last frost date. Planting flowers in spring is the most popular time, but perennials do fine if planted in early fall in the North and late fall in the South.
Flowers to plant in September
English marigold (Calendula) has deep orange petals, which are perfect for a hot border or for cutting. It's easy to grow – from an autumn sowing it should flower from May. Sow direct into shallow drills or on the surface of moist peat-free compost, in pots.
Autumn is a great season for annuals, 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.