May 2011
Multiplication by Division, from Kathy B.
Well, spring is finally sprung and everything’s popping up more quickly than seemed imaginable only a few weeks ago. Spring is an excellent time to make more of what you already have by the magic of division and cuttings. Spring is generally one of the best times to divide since most of the plant’s food reserves are stored in its roots and the plant is just ready to grow! What’s more, spring’s cool damp days are ideal for allowing the new plants to quickly grow new roots without the need to shade or mist delicate leaves to protect them from the hot sun. Gray drizzly days provide ideal weather for dividing plants.
Spring bloomers such as lungwort and hardy geranium are best done as early as is feasible so
the plants can establish themselves in time to put on a good show. If you are new to the art of
dividing plants, start out with easy-to-divide plants such as hardy geranium or daylilies. In the
case of hardy geraniums, just lift out a clump from the ground and it will almost break apart for
you. Replant the sections of root that are sprouting or that even look like they may sprout and
you’ll soon have a lovely blanket of aromatic foliage and pretty spring flowers. Daylilies will
require a bit more exertion, particularly if it’s a large overgrown clump, but it’s tough to kill
them nonetheless. Lift out the clump with a digging fork or spade and, if it’s still a manageable
size, you can break the clumps apart with your hands and replant the divisions. If it’s dense and
overgrown, I’ve had good luck just slicing into it with a spade and breaking it apart into smaller
clumps and replanting. Ornamental grasses are another physically challenging plant to divide if
allowed to get too big – in fact, after a few years, a clump can get so big, fibrous and heavy that
it’s nearly impossible to divide without heavy machinery and a chainsaw, so don’t allow them
to get so large that you can’t do it without hiring many strong young men (unless that was your
secret goal). In fact, many plants will actually begin to decline without division, such as bearded
iris and Siberian iris, although those two are best divided after they’re done blooming in the
spring if you don’t want to lose this year’s flowers. Woody centers that don’t bloom means it’s
time to get in there and split it up.
Certain plants don’t easily lend themselves to division, particularly taprooted plants such as
baptisia, gas plant, baby’s breath or oriental poppies. That’s not to say they can’t be
propagated, but you’re better off taking stem cuttings (lavender, for instance) or root cuttings
(poppies are reputedly very easy to propagate this way.) Another good rule of thumb to
remember is that the slower growing the perennial, the more it resents division and it will take
a while before it will put on a good floral display. Peonies (best divided in the fall anyway) are a
good example of this. However, if your goal is more plants, division is a rewarding way to
increase your numbers of favorite plants and soon have enough to give away to friends - Stella
d’oro daylilies, anyone? Anyone at all?? Anyway, happy planting gardeners!
