Time for your September garden fine-tuning

September 9, 2018

As the summer winds down, I’m happy that it’s time to fine-tune my garden. Now, for example, is the perfect time to dig and divide many different kinds of crowded perennials such as daylilies and garden phlox.

I’m also planning to move some young volunteer plants such as golden Alexanders and culver’s root seedlings to the woodland edge. I’m hoping these attractive natives will hold their own against the pretty but too aggressive Virginia waterleaf already well-established in the ravine.

I’m sorry to admit that the peony display in my new city garden consists of only one plant, but now I have a good chance to remedy that deficiency. September is the time-honored month to plant bare-root peonies. For those gardeners who have old peonies that are sulking in too much shade or in poorly-drained soil, now is also the time to dig and divide peony roots and replant them in a better location. Place each root so that the pink buds, or “eyes,” are 1 to 2 inches below the soil surface.

I know I won’t be able to resist cruising through a garden center or two this month on my never-ending quest to find some new, irresistible perennial, shrub, or tree to add to my landscape. There’s plenty of growing season left for new transplants to establish themselves before winter, and September weather is generally easier on both new transplants and the gardeners who plant them. You may even find an end-of-season bargain or two.

Along with the to-do list for autumn, there are also some garden chores that are best postponed. Feel free to procrastinate until spring before digging and dividing many other kinds of perennials, including delphiniums, coral bells, hostas, astilbes, and salvias. All are better divided in the spring than in the fall.

Also ignore for now any crowded asters, boltonias, tall sedums, goldenrods, and other fall bloomers, simply because you wouldn’t want to interrupt their autumn show.

If any of your ornamental grasses have developed a dead spot in the center of the clump, make a note to dig and divide those plants after new growth appears in spring. For now, just enjoy their long-lasting, late-season beauty.

While you’re making a list of what not to do now in the garden, also note which perennials resent transplanting and are best left undisturbed in any season. They include butterfly milkweed, gas plant, blue false indigo, bugbane, Lenten rose, bleeding heart, goat’s beard, monkshood, and lupine.

The best opportunity for really improve the soil in an existing garden is anytime you’re planting something new. Dig a bucketful of compost into every planting hole.

Update hourly