September To Do in the Garden

By Gary Crispell, EMGV

August turned out to be anything but cool compared to July. In fact, I spent more time indoors this August than in the combined months of June and July. Admittedly, part of this was due to another back surgery, but still, the scorching heat made the outdoors less inviting. It was either oppressively humid or blisteringly hot – take your pick. It was the kind of heat that made you doubt the effectiveness of your deodorant as soon as you stepped outside. To make matters worse, here in Durham, it seems the land itself is hydrophobic. Radar would show rain all around, sometimes directly overhead, but the rain gauge seemed oblivious, insisting, “Rain? What rain?” Then came Hurricane Idalia. (Doesn’t that name sound suspiciously like a new variety of sweet onion from, say, Alabama?)

As for the garden, it is quite pathetic. A few scattered blooms here and there, it resembles a perennial garden in September rather than August. The gaillardia (Gaillardia pulchella) deserves special mention. Year after year, when everything gives up due to the relentless drought, the gaillardia soldiers on. It’s a champion for xeriscaping. Other warriors include Chinese forget-me-nots (Cynoglossum amabile), Zinnias (Zinnia elegans), not perennial but certainly drought-hardy. Purple coneflowers (Echinacea purpurea), two species of cosmos (C. bipinnata c.v. Bright Lights & C. sulphureus), African marigolds (Tagetes erecta), and the first signs of a promising wild ageratum colony (Conoclinium coelestinum) managed to thrive. We could potentially get a second blooming from some of the perennials if we cut them back, but we’re reluctant to disturb the goldfinches feasting on the seed heads.  It’s quite a spectacle.

(Left to right) Gaillardia pulchella, Cynoglossum amabile, Echinecea purpurea, Scattered blossoms of the African marigold, Tagetes erecta. (Image credits: Gary Crispell)

As for the rest of the garden:


Do you have a cool-season grass lawn (fescue, bluegrass, perennial rye)? Is it in need of some repair? Now is the time. Whether you are spot seeding, overseeding, or starting all over again, September through October is prime time. Do it when the soil is still warm. This not only promotes good germination, but it gives the grass time to put down a strong root system and a healthy top before the trees try to suffocate it with their haphazardly discarded used foliage.

Scratch up the bare spots or core aerate the whole lawn, or if renovating/starting from scratch, shallowly till the area to be seeded. Work in the appropriate amount of lime and fertilizer. You’ll know the appropriate amount because you got a FREE SOIL TEST earlier in the year. (Materials and instructions are available at the Durham County Extension office at 721 Foster St.) Sow the seed, then lightly pack the soil down to ensure good seed/soil contact. Cover the seeded areas lightly with wheat straw. (All that you put down should be raked up later.) Water everything well, then keep it sufficiently moist until germination. It will need about 1” of water a week, preferably applied in two sessions.

Do not fertilize any warm-season grasses (Bermuda grass, zoysia, centipede) until they start to green up in the spring


Please do not prune (except for storm damage mitigation). Pruning should wait until after Thanksgiving or later if November turns out to be exceptionally mild. Instead, sharpen and oil your tools and equipment so it will be ready when needed.


All of the usual pest suspects from July and August are still lurking in the garden and they are hungry. For example, woolly adelgid on hemlock, and spider mites on many conifers (cone-producing plants). These insect pests seem to know when plants are under stress and will take advantage of the opportunity.  Pests to look out for: Tea scale sucking away on euonymus and camellias, lace bugs on azaleas (especially those grown in the sun), and pyracantha, as well as the ubiquitous aphids.

Spray pesticides only when necessary. Think organic first. Read the label and follow the instructions. If you need assistance identifying a pest, contact the Master Gardener office at 919-560-0528 or


It is time to dig and divide spring and summer flowering bulbs such as daffodils, iris, and daylilies (Hemerocallis). Daylilies, like to be handled a little rough (and you thought this post was rated G) by digging and splitting the bulbs/tubers apart. They will be ecstatic (as soon as they recover from the rough stuff) and will reward you next spring by blooming their li’l hearts out. And, you won’t have to repeat the process for two or three years.

Peonies like to get in on the action in a similar, but different fashion. This is the best time to transplant them. Dig a wide circle around the root ball and gently lift them. Transplant to their new home at the same depth or slightly higher.  If you plant them too deep, they will not flower for you. Cut back the old stems, mulch heavily and water deeply.


Go outside just to be…outside. At some point, the humidity will decrease to a tolerable level, but the temperature will remain in the sweet range. That range is after, ‘as-few-clothes-as-possible’ and before sweatshirt weather. “Sweet spot,” he repeated. That’s when the morning coffee on the veranda is divine or the afternoon beverage is equally so. “Just do it.” Watch the hummingbirds play at Top Gun while they try to fill up before setting off for South America. Plant a fall garden. Go pansy shopping toward the end of the month. Replace some old overgrown landscape plants with natives. Go to a dog park. Even if you don’t have a dog, watching dogs’ exuberance while they run and play is oddly relaxing and a stress reliever. Enjoy September, Y’all.

Reading and Additional Information:

To find plants that could work in your garden or to get additional information on particular plants go here:

Planting Fall seeding of Cool-Season Grasses:

Fall focus on succession planting and pollinator friendly plants: