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.
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).
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.
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.
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.
Late summer or early fall is an excellent time to plant mums, one of the symbolic flowers of the season. Practically any time in September that strikes your fancy is a good bet, so long as it's at least six weeks before the year's first frost.
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.
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 general rule of thumb is that most plants freeze when temperatures remain at 28°F for five hours. Of course, there are exceptions to this rule. Seedlings, with their tender new leaves, often give up the ghost when temperatures dip to 32-33°F. Tropical plants have differing low-temperature thresholds.
While you can plant a late planting to the first frost date, it's always best to allow as much growing time as possible. If you missed the spring planting, then calculate which vegetables you can grow now and still have a harvest before the first frost.
While spring may be the most common season to tend to your flower garden, that doesn't mean you can't grow something beautiful this fall! August is often the perfect time to start planting because it encourages root growth in the soil before things start freezing, giving your garden a head start for the spring.
You actually can plant many different edibles and ornamentals in July to squeeze out a second harvest or brighten up faded flower beds, containers and planter boxes.
When to Plant Marigolds. Young French and signet marigolds can be planted from spring through midsummer, but the tall African marigolds are best planted right away in the spring (after danger of frost has passed) because they are slower to mature and produce flowers.
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.
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.
It's not too late to plant in your garden! In much of the country, summer still is full steam ahead in August. In other regions, the hint of cooler evenings mean the growing season is beginning to slow down. But regardless of where you live, there's plenty of time left in the season left for growing things!
Plant wallflowers, forget-me-not, Bellis, Primula, Viola (including winter pansies) and other spring bedding plants in prepared ground or pots.
It's time for planting fall color, such as mums and asters, as well as sprucing up planter boxes. You also may be surprised to learn that it's the best time of year to plant perennials and shrubs (trees, too!) while plants still have an opportunity to establish their root systems before the ground freezes.
Garden Mums
Chrysanthemums are a classic choice for fall porches and patios. They are easy to grow and loaded with flowers in red, yellow, purple, orange, white, pink, and more. Morgana Red has beautiful dark red flowers that attract butterflies.
From early fall through most of November is one of the best times of year to plant spring-blooming bulbs, cool-season annuals and vegetables, as well as many trees, shrubs, and perennials.