September Garden Chores

How many of us gave up and ignored the garden in August, the heat driving us indoors? Raise your hand if that’s you. It was definitely me. It was too dang hot and the perennial beds were one big, complicated mess. I opted to let the plants fend for themselves. As the cooler days and nights of September arrive, I’m sort of regretting that decision—-the weeds took over in a few short weeks. So, chore number one on September’s list, weeds. Take a quick stroll through your garden and check the weeds. Check yourself too, and see if you can id them.  If you're like me, I failed on the id part. I don't know my weeds as well as I know my beloved plant children. That's about to change, because every gardener worth their weight in zucchini needs to know the competition.

1. Weed War

The purpose of weeding is to stop the weed seeds from spreading, and hopefully, lessen the weeds for next season.

  1. If there's no time for pulling, use super sharp snipers and cut those flowering-soon-to-be-seeds off. This buys some time and helps reduce the spread. Remember, one year's seed is seven year's weed.

  2. Weed after a good rain. The weeds are easier to pull up, root and all.

  3. Avoid mucking around too much in wet soil, though. If you can reach across, instead of stepping on wet soil, do so. Rake up the soil when finished to reduce compaction and runoff.

  4. Do dispose of the weeds. Unless you're a composting guru, it's probably best to throw weeds out with the trash.

Compost needs to be hot to destroy the weed seeds. Turning up the temperature is as easy as turning the compost pile, but for the beginner, skip adding the weeds for now. You want your first go at composting to be successful. You don't want to spread weeds into the garden directly from your compost bin next year. For more information on weeds and compost, click here on Weed Science Society of America's site. (Lots of other great information on this site, as well. All about weeds.) And because some weeds are good to keep, read here

Let's identify a few of the bad guys.  Click on each picture for information.

Pennsylvania smartweed in bloom. Polygonum penslyvanicum is a weed that thrives in moist areas and is blooming now. Cut off seed heads if you don't have time to weed, but weeds pull up easily, especially in dry soil. Pulling these is not a time consuming task. Just FYI: Smartweed is in the same family as knotweed. So, there's that. Persistent is it's true name. Click here for more information about this weed, and a map of where you'll find it. (Hint: Everywhere but a few states out west.)

Yellow nutsedge or nutgrass, Cyperus esculentus, thrives in areas of poor drainage. You'll find it in places where water pools, and sprinklers are leaking (hence it's infestation in your lawn), but once established it can tolerate drier soils. Be sure to snip flower heads. Click here for more information on this weed.

Ground cover weeds: The Worst

A great book for identifying and understanding garden weeds. Click here for more information.

For spot places that need extra care, try layered cardboard or newspaper smothered in mulch, which is very effective. Weed the area first, water it well, then put down cardboard or newspaper, and mulch. If you want to plant in that area, cut small x's in the cardboard and continue to water the plants. Substantial perennials and shrubs work best. 

Weed Tip: Purchase the book pictured here for easy identification of weeds. Click here

2. Lawn Care

  1. Now is the time to reseed bare places, aerate compacted places, and add an inch layer of compost to the lawn.

  2. Suggested time to add a layer of compost: mid-September and again mid-October to early November.

  3. On the final mow, be sure to lower the mower blades to 3" instead of 3.5". Leave your lawn clippings unless you've had to wait too long to cut and the grass clippings are matted down, then remove and compost.

  4. Consider adding clover to your lawn as it helps with nitrogen fixation, helps push out unwanted weeds, doesn't get over 4-8" tall and grows well with grass. For more information on clover, read here.

3. Cutting Back and Dividing Perennials

Helenium 'Mardi Gras' blooms mid-summer through fall. it non-stop blooms for 2-3 months. It is unbeatable for color and needs no deadheading to keep blooming.

  1. Many perennials are starting to yellow indicating it's time to cut the leaves back, and divide if necessary. Remove yellowing leaves now (hostas are a good place to start).

  2. Remove spent flowers, cutting back to plant level.

  3. Remember too, that perennials benefit from division every 3-5 years, so examine what perennials are starting to bleed out in the middle (dianthus, phlox, shasta daisy), and divide and transplant for a healthier plant. It's an inexpensive and easy way to grow your garden. For a how-to on dividing perennials, read here.

Perennial Tip: Spring-to-early-summer blooming perennials divide in fall, late summer-to-fall blooming perennials divide in spring.

Gardener's rule of thumb: Divide when you have the time.

Landscape Tip: The longer you live in a landscape, (unless you have no trees) the shadier it gets. Is it time to re-evaluate perennial beds? Which perennials are leggy and reaching for the sunlight? Or the opposite? Which ones are now getting fried from too much sun because a tree was removed?  Or is the garden beautiful in spring but lacking in fall? If so, check out the store's great selection of fall perennials: Anemones, Joe Pye Weed, plumbago, sneezeweed, asters, false sunflower, grasses and more.  

Peony Tip: Peonies prefer transplanting and dividing in September. For how to transplant peonies, here.

Hostas make a great groundcover and display with their showy leaves, but they are the first perennials to die back in fall. Don't be afraid to go ahead and cut them back. A few new leaves will emerge as temperatures vary, but that's one less job for fall clean-up. Do the same for other perennials as they begin to fade.

Hostas make a great groundcover and display with their showy leaves, but they are the first perennials to die back in fall. Don't be afraid to go ahead and cut them back. A few new leaves will emerge as temperatures vary, but that's one less job for fall clean-up. Do the same for other perennials as they begin to fade.

4. Pruning & Fertilizing

Do not prune shrubs or trees. For questions about pruning shrubs in fall, read here. You can continue to remove all dead/diseased/damaged/dying wood on shrubs and trees, which is where pests and disease hang out. Pruning pushes out new growth that won't have a chance to harden off before cold weather arrives, causing potential die-back. For this reason, skip the fertilizing now, too. July 31st is the final day for fertilizing your landscape plants. 

5. Plant Trees and Shrubs

Seiryu maple in fall. Consider adding fall color to your garden now. (Picture courtesy of Chris Stone.)

September and October are good months to plant trees and shrubs. The soil temperature will stay warmer than the air temperature as night temperatures drop, forcing plants to focus on root growth over shoot growth. That's a good thing, since the goal is to have a good root system. Traditionally, we get more rain in the fall and early spring than in the summer, which is another good reason to plant now. That said, be sure to check the amount of rain you're getting and don't assume you can skip watering. Establishing plants with consistent watering is key to healthy, drought resistant plants in the future.

The store is getting in truckloads of new stock now. 

6. Plant Veggies, Swap out Containers, Plant Bulbs

Veggies: Plant Greens Now

Fall transplants are in! Plant mustard, radish, mixed greens, turnips, and more for a fall harvest. Here's a quick how-to on planting and growing greens. 

Container Gardening: Spruce up your SEasonal Pots

It seems early for pansies and violas, but getting them in the ground now establishes good root systems for a beautiful fall show (that lasts well into next growing season). Plant now, and if the pansies begin to get leggy, shear them very short (about 2"), which forces root development, and creates a tighter plant. New growth will happen quickly and they'll be blooming again soon. Mix with annual mums, heirloom pumpkins and evergreens for a great fall display. 

Photo courtesy of Brenna Henley, BB Barns container designer.

Bulbs: Purchase them now

Decide on your bulbs and purchase now. Where does the spring garden need sprucing up? How many bulbs and which varieties are needed? We sell out fast once the weather starts cooling down, so don't dawdle. Make your list and purchases now. 

If you're read this far, then you know September is a busy month. Expect October to be just as challenging. If you want more information on the topics discussed here, the upcoming September blogs will be dedicated to more in-depth look at lawns, planting bulbs and dividing perennials.  


Cinthia Milner is the garden coach, and blog writer for BB Barns. 

BB Barns Garden Center serves all of Western North Carolina, upstate South Carolina, and Tennessee.