I’ve been receiving calls and emails about Zora Ronan’s upcoming open gardens this weekend and hearing from people who plan to make the trip to see her daylilies. For those of you who cannot attend, Zora sent some tips on dividing daylilies and other general advice:
When or if to divide a daylily is a decision to be made based on the plant’s health. If it is not looking unhealthy, is still blooming freely and has not outgrown its space, there is no reason to disturb it. I only divide when one or more of those problems occurs. Daylilies vary greatly in how fast they become crowded. I have some that get divided every 4 years or so and some that have been fine for more than that time. The biggest problem in waiting to divide until the plant is very overgrown is that it can become very large and hard to handle. When I do divide, I replenish the soil with lots of compost and a bit of peat.
Daylilies are considered the perfect perennial because they survive and thrive with very little care. However, good nutrition and adequate water is always going to improve daylily performance. I do fertilize lightly every year with lawn fertilizer (no herbicide). Daylilies can use a bit more nitrogen than other perennials to keep the foliage a nice healthy green. I apply a 3-month time released fertilizer in the early spring–never any fertilizer after August 1. If you have a good supply of compost, top-dressing with that every year is also beneficial and can probably take the place of artificial fertilizer.
Any dividing is best done in spring or after bloom has ended. I would not divide any later than early to mid-September – daylilies need about 6 weeks to settle in before winter arrives. We never know when that is going to happen.