September begins with a last taste of summer, and ends with the first cool days of fall.
This is a busy month for gardeners who can transition from summer vegetables like tomatoes and eggplants to the cole crops of fall.
It’s also the time to prepare lawns for winter and prune trees and shrubs.
Refresh home with fall annuals
Give your garden some fall love and instant color by planting annuals, such as pansies, mums, celosia, coleus, ornamental peppers and more.
For variety, try flowering kale and flowering cabbage.
Divide and plant perennials such as hosta
When your hosta and other perennials begin to look weathered and exhausted — or they’re just falling over — it’s time to divide and conquer the overcrowding problem.
Most perennials need dividing at some point, usually every two to three years. Otherwise, your blooms will be competing for nutrients and water. Find out which perennials need dividing now.
Plant perennial ornamental grasses
Ornamental grasses add drama to containers and landscapes. They are among the most drought-tolerant, deer-resistant and easy to establish plants you can grow. Most ornamental grasses ask for little more than room to grow and average soil. Once they’re settled in, they are low-maintenance and long-lasting.
Prune ornamental grasses in the fall and provide an annual fertilizing. Choose ornamental grasses with care and know your hardiness zones. Some of the most popular grasses, like purple fountain grass, are not cold-tolerant and unless you’re in frost-free zones, they should be treated like annuals in planters and borders.
Bring plants inside before the first frost
Trends point to a continuing love of greenery indoors, so bring plants inside for a second life during winter. Cactus, succulents, geraniums and herbs overwinter indoors as long as you take precautions.
Trim dead leaves and repot plants in fresh potting soil. Keep your plants in a sunny spot indoors. Don’t worry about feeding in winter, just water according to instructions on the plant tag.
Plant cool season vegetables now, such as spinach, lettuce, broccoli, cabbage, kale, Swiss chard, Brussels sprouts, cauliflower and others. Read more about Pacific Northwest regional gardening tips.
Start planning your cool-season gardens. Plant annuals in mid-September in cooler areas and at the end of the month in warm inland areas. Consider adding sweet peas, violas, poppies and forget-me-nots. Read more about North California Coastal regional gardening tips.
Protect your landscape from wildfires, especially near the coast. Cut away brush and weeds, and clean underneath shrubs and trees. Read more about South California Coastal regional gardening tips.
Now is the time to plant succulents, including cactus and agave plants. Read more about Southwestern Desert regional gardening tips.
Keep perennials happy with an application of several inches of compost. Read more about Western Mountains regional gardening tips.
Set out lettuce, spinach and onion seedlings now for harvest before frost. Read more about High Plains gardening tips.
Replace faded summer annuals with fall favorites like mums, pansies and flowering kale. Read more about Northern Midwest regional gardening tips.
Tidy the garden, but leave some seed heads for birds and pollinators. The birds will appreciate seeds. The faded blooms of bee balm and other perennials will nourish pollinators. Read more about Central Midwest regional gardening tips.
Divide and transplant peonies through the end of September. Remember that the “eyes” must not be buried more than an inch or two beneath the soil surface. Read more about Mid-Atlantic regional gardening tips.
As your garden winds down, build vegetable garden soil by sowing cover crops. In the spring, you will turn this “green manure” under to improve soil fertility. Read more about New England regional gardening tips.
Refresh containers with cool season annuals like coleus and pansies. Look for plants in warm harvest colors like burgundy and orange. Read more about Upper South regional gardening tips.
Plant bulbs six weeks before first frost. Bulbs like well-draining soil, so amend beds first with compost. Read more about Middle South regional gardening tips.
Test soil in vegetable and flower beds, amend according to results. Get soil tests through your local Cooperative Extension Service or purchase a kit at The Home Depot Garden Center. Read more about Lower South regional gardening tips.
Remember to water lawns, vegetable and flower beds frequently during dry times. Gardens need one inch of water a week, either through rain or irrigation. Read more about Coastal and Tropical South regional gardening tips.
Plant shrubs and perennials now. Wait until hurricane season is over before planting trees. Read more about South Florida regional gardening tips.
Check out the gardening year at a glance: