Divide and conquer your perennials

8/31/2010

Yippee! It is time to get a few new starts of some of my favorite perennials! Most of the time I am loading a wagon at my favorite home and garden center, but this time, I'm filling my wagon right in my own backyard. I split one gigantic hosta near my driveway and split it into 20 nice starts and used it to line three flowerbeds. Bonus!

Landscape consultant Allison Wood-Osmun says early fall is a great time to divide hosta, daisies, coneflower, phlox, lambs ear, asters, sedum, baby's breath, beebalm, black-eyed Susan, coreopsis, peonies, yucca, geraniums, and even out-of-control shrubs.

Where to start

Before you start dividing, figure out what you will do with the extra plants. You could even dig the new holes before you start uprooting the current plantings so you can get them into their new spot as soon as possible.

Here are a few signs that your plants need to be divided: First, look at the plant's root system. If it is tightly packed and looks like it has no room to grow, it is a good candidate to divide. Next, look at your pictures from last season. Do you notice closely spaced blooms? Maybe you see smaller flowers. Both are clues that the roots need more room.

Get digging

Dividing your plants might take some muscle, but you get more plants to add to your landscape in return. Before you put the spade into the ground, cut off any dead or broken parts of the plant.

Next, dig around the outside of the entire root system with a long spade. "If the root system is large, you might need a garden fork to help pry it out of the ground," Mrs. Wood-Osmun says. She recommends keeping the root system intact as much as possible to minimize the shock to the plant once it is settled into its new location.

Muddy idea

Keep the new hole about the same depth as the one the plant came from. You want the plant's crown to be at the soil line — not too high, not too deep.

Mrs. Wood-Osmun says she thinks this technique will help your transplant thrive: "Basically, you [make] a slurry of muddy water in the bottom of the new hole before you set the roots in there. This will focus the moisture at the bottom of the plant where it will need it most. It also helps soften the sidewalls of the hole, and that will make it easier for the roots to push into the soil surrounding the newly excavated spot."

After digging the hole, Mrs. Wood-Osmun says, fill the bottom with water and mix it with the loose soil. Next, set the new plant into the hole. Then, add another one-third of fill soil and more water. Cover the rest of the hole with soil and water again to settle the plant in its new home.

A little off the top

Once the plant is in its new location, you will need to prune back some of the current growth. Leave about one-third of the foliage on the plant and prune off the rest. This will take a little pressure off the root system to feed the foliage and let it spend most of its energy regenerating roots for next year. Keep the transplants watered until the first hard frost. Keep transplanted shrubs watered until after frost.

Beware of sharing

If you have too many plants and want to give some to a friend, be sure you aren't giving them more than they bargained for. My sweet Aunt Phyllis in Bedford, Mich., was sharing a few plants with her sister, my Aunt Leota in Swanton. The sisters love to exchange plants. But, unfortunately, Aunt Phyllis' group included a few starts of poison ivy, and now Aunt Leota is just itching to get out of the garden. Oops!

Contact Kelly Heidbreder at: kheidbreder@theblade.com.