City Gardening

Lambs Ears

How did your plants spend their summer vacation? Walk out into the garden and take a look around. Have the Siberian irises crowded out the phlox? Are the stems of your yarrow lazily flopping over its neighbours? Has the centre of the your silvery artemisia browned-out? Did you notice how much smaller the peony flowers were this year than last?

Dividing perennials that have outgrown their space, become lanky and limp from overcrowded stems, ceased to produce large, showy blossoms or that have become woody enough to die-out in the centre is like treating them to a spa – it rejuvenates and keeps them healthy.

Generally, perennials that bloom in the spring and early summer can safely be divided in the fall. These include hardy geraniums, columbines, coral bells, pulmonarias, hostas, centaureas, Siberian irises, oriental poppies and dianthus. But with care, many mid-summer bloomers such as phlox, yarrow and daylilies can also be divided during the cool days of fall. Autumn is also the only time to divide or move herbaceous peonies. These and other fleshy rooted perennials such as oriental poppies have been busy over the summer storing energy in their thick roots. Moving them in the spring, after winter and early spring growth has depleted that energy, means these plants have less of a chance of recovering from being divided. No matter the plant, divide it early enough in the fall to allow it to form a good root system before the ground freezes – generally, at least six weeks before winter sets in.

To divide perennials, wait for a cool, overcast day. Roots exposed to sun, heat or wind can become dried out in a very short time. If you must work on a sunny or windy day, keep the roots shaded and sheltered from the wind – it’s also a good idea to keep a bucket of water handy.

When you’re ready, lift the plant from the ground with a garden fork, digging the tines into the soil under the clump. Gently exert enough upward pressure to leverage the roots from the soil. Work your way around the plant, inserting the fork and prying up the roots until the clump is free.

How you divide up the plant depends on the size of the clump and the firmness of the rootball. Roots of nepeta, geraniums or coral bells are fairly loose and easily teased apart with your hands while those of mature hostas, for example, require the double-fork method. This involves inserting a garden fork into the centre of the clump, then placing a second fork back-to-back to the first one. I find this method a bit awkward for one person to perform because it requires that both forks be pushed in opposite directions at the same time – I don’t know about your dexterity and strength, but I find myself all elbows and thumbs. I prefer dealing with these stubborn roots with a dull knife – or let’s be brutally practical – a hatchet. Just wield it as you would a kitchen clever, and before you know it, your plant is nicely chopped.

Once divided, discard the older, browned-out part of the clump. Plants age from the middle toward the outer edges, so the older parts will be in the middle and the younger ones will be clustered around the perimeter. Replant the young divisions into the garden right away to keep them from drying out, or pot them up to give to neighbours and friends.

Papa, Mama and Baby BrunneraBrunnera ready to divide

Roots on lambs ears