Time to Divide: Perennials That Is

2017 May 24

It’s time to divide some garden perennials. You might ask, why divide? I agree with four of the main reasons listed on the better Homes & Gardens website. I want to keep them healthy, beautiful, and within bounds.  I also want to make more plants.

I especially keep my eye out for clumps of perennials early in the season before they start to bloom. The ones I divide most frequently are yellow Stella D’oro Lilies (Hemerocallis stella d'oro), native blue Rocky Mountain Penstemon (Penstemon strictus), pink Yarrow (Achillea 'Paprika'), white Shasta Daisies (Leucanthemum × superbum), blue Fleabane (Erigeron 'Azure Fairy'), purple May Night Sage (Salvia nemorosa) and yellow Oakleaf Sedum (Sedum ybridum).

The lilies and daisies produce fewer and smaller blooms if they are too crowded.  If fact, one lily clump I missed last year didn’t produce any flowers while the less compacted ones nearby had an abundance of  blooms. I find this with Shasta Daisies as well. My Penstemons and Fleabane tend to die off in the center if they don’t get divided every few years.

It’s a different story with pink Yarrow, Sage, and Oakleaf Sedum.  These plants are vigorous spreaders and can overwhelm other plants.  It seems they’ll stay a reasonable size for a few years and then suddenly one year, they’ve grabbed lots of new territory.  This year I dug out a lot of yarrow from around my struggling Barberry shrubs (Berberis thunbergii). I love Oakleaf Sedum in my rock gardens.  However, it seems to stretch out over the surrounding gravel paths and somehow survive there.  While I didn’t necessarily color only within the lines in my coloring books as a child, I don’t like plants growing outside the beds as once they start, dirt and weeds collect around them causing an unsightly mess and more work later on!

Other plants I watch are Creeping Charlie (also called Creeping Myrtle, Glechoma hederacea), Creeping Buttercups (Ranunculus plentiflorus), and Lilies of the Valley (Convallaria majalis). When I visited the Arbor Day Farm in Nebraska City last year, folks referred to Creeping Charlie as an annoying weed and tried to remove it whenever and wherever possible.  I find in drier areas of my garden it will often grow when nothing else will.  I like the tiny purple flowers early in the spring. Also, if the soil is wet, it is very easy to pull up as most of its roots are very shallow.

I enjoy the bright yellow of the Buttercups, but they border on being invasive and their roots are a bit harder to dig up.  This year I’m transplanting some to a part of the garden that gets the most wind and little water.  Other plants I’ve tried haven’t been happy there.

My Lilies of the Valley aren’t as beautiful as some I’ve seen in other parts of the country.  The flowers tend to hid under the leaves, but I still keep them.  They tend to be harder to remove as their roots form dense clumps.  Before digging, make sure your soil is moist and your shovel sharp!

What to do with the plants you’ve pulled out? It turns out I always have areas of the garden that need some help.  I try to improve the soil in areas where plants have died out and then transplant the thinned out clumps.  I also check to see that the new area receives enough water. I am also happy to share plants with other folk – as others have done with me in the past. If I can’t get them transplanted immediately after digging, I try to keep them in a cool, shady spot and make sure they don’t dry out.

By the way, I’m doing the dividing now.  My greenhouse is full of new perennials I’m holding off on planting until our weather warms up.  But the hardy perennials already in the garden are doing very well and didn’t seem daunted by last week’s 20 deg. F low (only two degrees higher than our record low on the date).

You can find photos and information on these plants at AlamosaFlowers.net.

"In the spring, at the end of the day, you should smell like dirt." Margaret Atwood in “Bluebeard's Egg “