Dividing perennials; plant sale; reminders

By John Fulton

[April 15, 2011]  What a difference a few 80-degree days made! One common maintenance chore evident last weekend was that of dividing perennials. There is no set rule as to when to divide perennials. Some may need division every three to five years, some in eight to 10 years and some would rather you not bother them at all.

Perennials will send signals to let you know that they would like to be divided. The signals to watch out for include these: reduced flowering, with the flowers getting smaller; growth in the center of the plant dies out, leaving a hole, with all the growth around the edges; plant loses vigor; plant starts to flop or open up, needing staking; or it just may have outgrown its bounds. These are the signs to look for and not a date on the calendar.

If division is indicated, spring is the preferred time to divide. Some fleshy-rooted perennials such as poppy, peony and iris are best divided in the late summer to very early fall.

Division is usually started when growth resumes in the spring. The process begins by digging around the plant and lifting the entire clump out of the ground. Then, using a spade or sharp knife, start to cut the clump up so that each section is the size of a quart- or gallon-sized perennial. Discard the old, dead center and trim off any damaged roots.

The divisions should be kept moist and shaded while you prepare the new planting site. After replanting, water well and protect the divisions from drying out.

Division is no more complicated than this. Some perennials may be more difficult to divide than others because of their very tenacious root system.

Division has as its primary goal the rejuvenation of the perennial planting so it can continue to perform the way it was intended. Many home gardeners have found that the process of division is more traumatic to the gardener than it is to the perennial.

Plant sale

Many people have been asking about the Master Gardener plant sale for this year. It is scheduled for April 30, from 9 a.m. until noon, in the Logan County Fair Special Events Building on the south end of the fairgrounds. The group will once again have a good selection of annuals, perennials, houseplants, heirloom tomatoes, peppers and a few other assorted items.

Reminders

• Mow the grass as it is needed. To do away with catching or raking grass, try to remove no more than one-third of the leaf blade. That first trip out with the mower usually shocks us how long some of the grass is.

• Broadleaf weed control is just around the corner for many weeds. Look at early May for the best control.

• Grub control is largely unsuccessful in the spring because of large grub size and a short life cycle. Look to August and September for grub control.

• Moles are becoming active, but controlling the grubs won’t help much now. Look to a noose or scissor trap or one of the soft baits with poison for control.

• The average last killing frost date is about May 5 for our area, and many gardening charts use May 10 for planting tender crops in our area. This would include squash, peppers, tomatoes, green beans and others.

• Prune flowering shrubs after they are done flowering. This will promote growth and, hopefully, maximize your flowers for next year.

• If you are interested in using the soil-applied treatment for Japanese beetle control on ornamental trees and shrubs, the earlier applications allow for better distribution in the plants. These treatments will not eliminate damage but will reduce it by 50-75 percent since beetles must feed until they consume enough of the insecticide in the leaves.

[By JOHN FULTON, University of Illinois Extension]