They always say fall is for planting, but if you live in a cold climate, don’t wait too long. You want your plants to settle in and become established for at least 4 – 6 weeks, before the ground freezes.
I like to get as much cleanup done in the fall as I can, because spring can go by in a wink. Even so, I’m hesitant to do a lot of late dividing of perennials. You can never be sure when a frost is coming and loosening the soil in fall seems to be an invitation to every vole in the neighborhood.
What the Heck
But I’ve always been one to push my luck. If you’re like me, here are a few perennials that seem to handle the disruption late in the season. Focus on these first.
I’ve found it best to divide spring blooming plants right after they flower. I won’t lose out on the blooms and since they are actively growing then and about to be fed, they are strong enough to regroup and re-establish.
But is spring is too busy for you, go ahead and divide in the fall. Just give them some extra mulch, after the ground freezes.
Summer Bloomers to Divide in Fall
Basket-of-Gold (Aurinia saxatilis) – This plant doesn’t really like being disturbed in the spring, so fall is the best time.
Coral Bells (Heuchera species) – Most varieties of coral bells are so easy going you can divide them any time. Just don’t wait too long in the fall, because their crowns are easily heaved out of the soil.
Coreopsis (Coreopsis species) – Coreopsis are such prodigious bloomers, it seems a shame to divide them until they’re done flowering.
Daylily (Hemerocallis species) – Just try to kill a daylily. Impossible. Divide whenever you want, but early fall allows them to start spring on a high note. Hardy Geranium (Geranium species) – Like daylilies, they come out of the spring gate blooming if you divide them in the fall.
Hosta (Hosta species) – Okay, these don’t really need to be divided at all. But if you want to make more plants, they recover quicker if divided in the fall. They’ll look sparse and sad for weeks in the spring.
Peony (Paeonia hybrids) – Here’s another plant that never needs dividing, but if you are going to disturb it, do it in the fall. Even then, they might not bloom for the first couple of years.
Phlox (Phlox paniculata) – Phlox will have time to recover from a spring division, but you can get ahead of the game by dividing in the fall, with no harm done.
Speedwell (Veronica species) – Veronica can get ugly toward the end of the season and dividing it in the fall seems like you’re doing it a favor. Don’t forget to mulch them, after the ground freezes. And don’t forget to remove the mulch in early spring, so the ground can warm up.