Dividing perennials: How to create many plants out of one.
If you need a little outdoor activity this month to burn off some of that "holiday cheer," you can achieve that -- and extend your landscaping dollars -- by doing a little perennial division. This is a method of propagation whereby you create many plants from one of your tried-and-true backyard favorites.
December is a great time to divide clumping plants such as agapanthus, chrysanthemums, daisies, day lilies, delphiniums, dianthus, ferns, hostas, kangaroo paw, Mexican sage, mint, Red Hot Pokers, society garlic, statice, violets, native grasses and even many ground covers.
After several growing seasons, these perennials can become overgrown and woody and begin to die out in the center. Dividing them every two or three years will keep them beautiful -- blooming and vigorous. It will also allow you to fill in your landscape without the expense of purchasing additional plants.
Part one, dividing:
First, cut off a third to half of the plant's leaves. This will lessen the work the roots will need to do to maintain the foliage of the new plants. Then dig up the entire plant, making sure to follow the drip line when digging and to go deep enough to get the entire root ball. Take care not to damage the root ball. Shake off excess dirt and remove dead leaves, flowers and stems.
Lift the plant out of its hole and place on level ground. Use two pitchforks or flat-edge shovels back-to-back of each other to pry and split the plant apart. If your plant is extremely large, you can divide it into several pieces in order to obtain the appropriate size. Only use the young, healthy-looking sections with intact roots. Discard any dried and woody plant parts.
Part two, planting:
Dig your new holes twice as wide as the sections you are going to plant. You should plant at the same depth as the original plant. If you are planting in unconditioned, native soil, mix in compost equaling one-third of the amount of the soil you removed. Water thoroughly and add a 3- to 4-inch layer of mulch around your new plants, keeping the mulch at least six inches away from the stem of the plant.
Master Gardener Lee Ann Ray contributed to this article. Have a question? Call the hot line, 408-282-3105, from 9:30 a.m. to 12:30 p.m. weekdays. Details: www.mastergardeners.org.