A seasonal post from Rick….
While hostas don’t require dividing like some perennials, quite regularly we are asked: “when is the best time to divide hostas”? The answer will depend on who you ask, what they have been told, or what is easiest for them and their gardening schedule. Some say early spring when the new growth points emerge and you can easily see where to cut between each to make another division. Others say in the fall. While hostas are extremely tough and will survive just about any kind of harsh treatment, I would disagree with these time frames. With over 35 years of experience in propagating hostas, my answer is July and August, and here is my reasoning and observations. Hostas do not put on much in the way of root growth until sometime in June. So a plant division made in early spring is expected to support all of its new growth with last year’s roots and only those that are still attached after it was removed from the main clump. A hosta divided in the late fall may not have enough time to establish enough new roots and store the amount of energy needed to get it through the winter and then support new growth in the spring. While both will probably survive, they won’t be as robust as those divided in July and August. During these months the plant will have time to put on new roots, add new leaves to store more energy, and set new eyes on the crown for a larger plant in the spring. Some people are afraid to cut a clump apart and break off some of the existing leaves. When we divide them, we purposely remove leaves from the divisions, especially those that may not have that many roots. We also remove all flowers. Some we replant with only one leaf. It is important that leaves and roots be balanced. Best to have fewer leaves so that the roots can support the divided crown. If done this way, and kept watered for the rest of the season, a much stronger plant will emerge in the spring. So if you have the time, and have hostas that you would like to divide, now through August is the time to do it.
Jul
13
2016
Fernwood Nursery & Gardens 
YOur reasoning is well presented, BUT…. Here in North Carolina one of our most noted hosta experts and breeders said to never plant hostas in July and August. Heat. Heat Heat. So there is definitely a climate factor in the equation.
John,
I’m sure that in the southern tier states that summer heat is a major factor in all types of gardening. My post was to answer the questions of our customers, and they are from New England and the Northeast. Thank you for that information and we will certainly pass that along to anyone from the south that may stop by and buy our plants, however that rarely if ever happens. Hope your gardening season is going well, and thank you for the helpful response! Rick
Thanks. We most assuredly live in different gardening worlds. I hope to visit yours someday.
Useful post!
Very helpful info. Can we talk blossoms? I leave them on so the pollinators can enjoy them but then cut them off because I think they are not that attractive. How do you handle your blossoms?
Judy,
We usually leave all of the blossoms on for the same reason you do, and for the hummers as well. Sometimes they are darting around our customers in the sales area as they feed on the fresh blossoms. I do think it is wise to cut the spent flower stalks before they go to seed. Otherwise the beds are full of unwanted seedlings.While some people dislike the flowers altogether and cut them off immediately, no harm is done to the plant. I’ll admit that some of the flowers on hostas are not that attractive, others are, and may be fragrant as well. Like the pollinators and hummers, I tend to appreciate them all, at least in a botanical way. Rick
I’ve always divided mine in mid-late May, when the leaves are up out of the ground but not yet unfurled and I can see what I’m doing. Thanks for giving me a different way to think about this.