Other tried-and-true, cool weather annuals for you to replace your tired summer flowers in either beds or containers—pansies, violas, dianthus, sweet alyssum, and snapdragons. For green interest, plant dusty miller and ornamental peppers, cabbage, and kale.
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.
Fall is Good for Root Growth
In the fall, the perfect combination of warm soils and milder weather create ideal conditions for newly planted trees, shrubs, and perennials. Warm soil temperatures encourage root growth – more so than in the spring when the soil is still warming up.
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.
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.
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.
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.
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.
Don't put down those garden gloves for the year just yet! Believe it or not, October happens to be one of the most fruitful times of year to plant spring-blooming bulbs, hardy vegetables, and shrubs of many varieties.
In general, aim to finish your fall planting about 6 weeks before your first expected frost date (8 weeks for evergreens). In Zones 3 and 4, you would count back from the latter half of September.
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.
Still, some other plants can grow in mild winters. Root vegetables like garlic, carrots, and radishes grow well in cold temperatures. So do leafy greens like collards, kale, and cabbage. However, even most cold crops grow best if they're protected from frost and freezing temperatures.
Planting in fall allows these plants to establish root systems that they can then bulk up over the winter. Also, in fall, there's usually more rain– which means less maintenance for you.
The latest time to plant for most vegetables would be the second week in June with a short harvest time. If planting crops that mature within 50 days, you could plant those as late as the last week in June, but keep in mind the weather will be turning cooler, especially at night. Cool crops are best for late plantings.
Also, do not cut back hardy perennials like garden mums (Chrysanthemum spp.), anise hyssop (Agastache foeniculum), red-hot poker (Kniphofia uvaria), and Montauk daisy (Nipponanthemum nipponicum). Leave the foliage. It's important to protect the root crowns over winter.
Flowers that come back up from their roots every year in the springtime are called “perennial” flowers. Some of the best perennial flowers to grow in a garden are peonies, daylilies, coneflowers, and hollyhocks.
Planting in September
Plant now beets, broccoli, Brussels sprouts, carrots, cauliflower, celery, fava beans, kale, kohlrabi, leeks, both head and leaf lettuce, mustard greens, onions, parsley, peas, potatoes, radishes, rutabagas, spinach, Swiss chard, and turnips.
Some fast growing fall crops like lettuce and radishes can be planted into late September, but many desirable fall crops like broccoli and carrots need several months of prime-growing conditions to mature before frost and low light levels set in. When in doubt, plant your fall crops a little early.
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.
Fall and Winter LEAFY GREENS
A beautiful sampling of some of the leafy greens you can grow in your fall and winter garden, including different varieties of kale, spinach, lettuce, chicory, and even wild chickweed! Spinach is a very fast-growing, cool weather vegetable.
Plant your fall vegetables so that the crops you choose have time to reach maturity before the first frost in your area. Find your first frost date, then count backward based on days to maturity for each type of veggie you want to grow. That's your ideal planting date.