One of the most commonly asked questions I get is: “When should I divide my hostas?”
First of all, I don’t think people realize that unlike perennial grasses, hostas don’t really need to be divided. I personally love the full, mature look they get when they fill their allotted spaces. But many people prefer a more orderly appearance, or just want to increase “the herd.”
Spring, when the “noses” are just poking out of the ground is considered the best time to divide, as long as you don’t wait too long. However, if the plants are up too far, you run the risk of damaging the leaves and stems during the process, and they will not recover for another year.
Summer is also fine, with the same caveat about leaf damage.
Fall is actually my favorite time. Many hostas look a bit ragged by then anyway, and the rigors of division won’t make them look much worse. I also recognize which hosta I’m digging and dividing. In spring, I don’t always remember which hosta is where! (Yes, I should label them!)
Once established, hostas can become fairly drought tolerant, but if you transplant in the fall, keep the roots well watered and mulch them so they don’t dry out. Otherwise, these Asian natives are one of the toughest perennials I know! The only thing they can’t seem to fight: slugs and deer. They rely on us for protection from those pesky predators.
Although some hostas—especially those with yellow or white leaves—can take more sun, hostas should be considered shade-tolerant. They all need some sun to grow well, but avoid a spot where they are exposed to super-hot late afternoon sun. If you do place them in sun, provide lots of extra water. I’m always surprised when I see hostas planted with full-sun perennials … they look good in spring and early summer when we generally get more rain here in Iowa but by summer? Ratty!
How to divide
Dig the clump, using a shovel or garden spade. Use a clean, sharp knife or shovel to cut dense clumps.
Small clumps can also be soaked and the roots then teased, coaxed, and cajoled into parting company.
For more information on growing hostas, consult the American Hosta Society.