No Separation Anxiety: Divide Perennials

When it comes to dividing perennials, please let me borrow from a fellow garden columnist who maintains the two most commonly asked questions are:

"What if I kill it?" Followed closely by: "Will it hurt?"

The answers are: 1. You won't, and 2. only if you hit your foot with the shovel.

The fact of the matter is, perennials need dividing every three years or so. They not only need it, they'll thrive as a result. If you grow clumping perennials, bulbs or plants with rhizomes or tubers, you need to divide them every three to five years to keep them healthy and vigorous.

Each year the typical perennial will gain in girth by growing new roots and stems around the outer perimeter of the previous year's growth. Eventually, these clumps get too big for their space int he garden and can't take up enough nutrients. Also, growth can become weakened due to competition and crowding. The result will be fewer blooms, or in worst cases, no blooms at all. Plus, division is a fast and inexpensive way of increasing your supply of favorite perennials.

Most dividing is best done in the fall. In our mild-winter region, you can easily divide this time of year. Some of the more common perennials that are candidates for division include: lily of the nile (agapanthus), aster, dahlia, delphinium, bleeding hearts (dicentra), fortnight lily (moraea), sunflower (helianthus), iris and plumonaria.

Above all, don't be afraid to divide plants! Simply dig the candidate up out of the ground, trying to get as much of the rootball as possible. It helps to soak the area a couple days beforehand to make the soil as workable as possible (if it hasn't rained). After digging out the plant, use a shovel, large knife or perennial spade to either half the plant or cut into thirds or quarters. You'll find that some plants divide easily, such as bleeding heart, while others like Siberian iris, are very difficult. With the latter, I've actually gone in with a hack saw to finish the job that a shovel couldn't. Obviously, you don't always need a delicate touch when dividing.

Plant divisions as soon as you can. Set them carefully into place and sprinkle soil around them until the planting hole is full. Do not tamp dirt in with a shovel or your foot as this can break off rootlets. Water with a little slow-release fertilizer and you;re set. If you can't plant right away, place divisions in a bucket or wheelbarrow and keep them damp, not wet. Placing a little damp newspaper around the roots will help.

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