Dividing Daylilies

Daylilies are tough, dependable workhorses in my garden.  They are very low maintenance and every few years, they generously provide new plants I can use to fill spaces in my own garden or give to friends.  

There is no magical time to divide daylilies.  Technically, any daylily that has two or more fans can be divided to obtain one or more additional daylilies.  As I mentioned in an earlier blog, though, the harder you divide them, the longer it takes for them to bloom again. 

So, when is it necessary to divide daylilies?  The general rule of thumb is that if the daylily is in optimal growing conditions, e.g. full sun if it is one that requires that, soil rich in organic matter, etc., and it isn’t blooming its best, it might be time to divide it.  Another indication that it is time for some dividing is when the foliage in the center of the clump becomes thin and straggly, along with fewer flower stalks and less blooms per stalk. 

Daylilies are tough as nails, so they will survive dividing and transplanting virtually any time.  The best time, though, is shortly after they finish flowering in late summer or early fall.  Here in North Dakota, I usually like to have my daylilies divided and re-planted by mid-September at the latest.  That gives them time to get their roots established before the ground freezes for the winter.

Daylilies can develop some pretty massive root systems and may require some muscles to get the root ball lifted so it can be worked with more easily.  It’s easier to do this if you clear away mulch, leaves, and other encroaching plants first.  I also trim the foliage back to about 6 to 8 inches, so that it isn’t flopping around and in my way.  Then, with a sharp spade, I dig straight down about 10 to 12 inches from the outer crown of the plant, doing this completely around the clump.

Once I’ve loosened the soil with the spade, I either use the spade or a garden fork to lift the clump from the ground, knocking off as much loose dirt as I can so it’s easier to lift.  I set the large clump to the side of the hole and then, again using either the spade or the garden fork, slice down through the center of the clump, dividing it into two parts. 

Now, here I have a confession to make.  I know a lot of people tell you to carefully tease the root clump apart to avoid damaging the roots.  Here’s my confession – I don’t baby my plants.  And, I think most people who have seen Wiese Acres will tell you that my plants don’t really seem to mind that.  So, I’ve been known to take my sharp spade, set it in the center of the clump, and give it a good whack right down through the middle of the clump. 

After the “whack”, I remove any roots or tubers that are badly mangled, or any that are mushy, shriveled or look otherwise unhealthy.  If it’s a very large clump or if I want a large number of divisions, I’ll more gently divide it down further, to about three to four nice sized fans. 

Only if it is a young daylily that has a small root clump and I'm dividing it just to get an additional plant, do I use the gentle teasing apart of the roots method to preserve the majority of the root ball. This is most easily accomplished using two garden forks to "wiggle" down between the roots to separate them, and then gently pulling the clump apart.
 

The next step I will take is to rinse the old soil off the root ball with a garden hose.  Then I soak the roots and tubers in a 10% bleach solution (1 cup bleach to 10 cups water) for about 10 minutes before re-planting.  With all the spring moisture of the past couple years, my daylilies have been prone to some fungal diseases, such as leaf streak.  The bleach solution may (or may not) help give them a fresh start in their new home.  Sources differ in their opinions on the value of the bleach soak, but bleach is cheap and 10 minutes isn’t very long, so I figure “why not?”

Then I plant the divisions just like I plant new bare root daylilies; water them in; give them a little TLC for the first few weeks; and place a 3 to 4 inch layer of wood or straw mulch around to protect them from the freeze and thaw cycles of winter.  Then I sit back and wait for next year’s glorious show!