The Homeowners Column

The Homeowners Column

April Activities in the Flower Garden

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

April is the time for activity in the flower garden. Remove any old stems that were left over the winter. Also remove any shredded leaves or winter mulch from the crowns of perennials and roses. Butterfly bush, caryopteris and Russian sage should be trimmed back to 6-8 inches. Wait until soil temperatures rise in May before adding additional mulch. Ornamental grasses should be cut down before new growth emerges.

Place any stakes around plants now so the plants can grow through the stakes. You know which plants need stakes. They flop every year. The inexpensive tomato cages spray painted green work well for many plants except tomatoes.

April is the time to move and divide perennials. A couple of exceptions include iris, peonies and some ornamental grasses. Iris should be divided after bloom in July and August. Peonies are best divided in September. Warm season ornamental grasses, those that don't show growth until May, should be divided in May.

When dividing you may just want to remove sections from the outside of the planting to reduce the size of the planting. It is also a less intrusive method for dividing hostas. For many perennials the most vigorous shoots are on the outside of the clump. This method works well for beebalm, mint and anything that spreads by runners to form a colony (or in the case of mint, its own country).

Everyone has their favorite method of dividing perennials and their favorite implement of destruction. I prefer a small spade and the highly technical method of "jump and wiggle." Shove the spade into the soil on the outside of the planting and continue around in the size of sections you want. I often have to jump on the spade to get through thick stems. Now wiggle the spade in the cut areas until the sections pop out.

Some people prefer digging around the clump and using two garden forks to pull the clump apart. Divisions can be as large as you want but four inch diameter sections work well for most plants. Smaller divisions will work but may not bloom as well for a couple of years.

Some plants have more of a central crown. These include daylilies, catmint, and astilbe. With these, dig out the whole plant and make divisions using a spade or garden knife or in the case of ornamental grasses an axe works well.

Replant divisions right away, plant into pots, heel into a pile of moist mulch for planting later, or put on your neighbors doorstep. Be sure to water plants thoroughly after replanting. Most perennials do not flower well the year they are divided, so dont be discouraged.

Some plants are invigorated by division or need to be divided every few years to keep them in bounds. A few of these are yarrow, boltonia, aster, perennial sunflower, obedient plant and black-eyed Susan.

A few plants do not like being divided and seldom need it. These include babysbreath, baptisia, lupine, butterfly weed, balloon flower, gas plant, bleeding heart and ladys mantle.

For a more thorough discussion of caring for perennials, there are a couple of great books available at your local bookstore: The Well-Tended Perennial Garden by Tracy DiSabasto-Aust and Caring for Perennials: What to Do and When to Do It by Janet Macunovich.

Gardeners often want to garden all year. If you can't move to warmer climates, how about a greenhouse? With any new venture, questions arise. What do I do about insects? What do I do with all these extra plants? If any one is interested in becoming a part of a new hobby greenhouse club and explore answers to these questions, than please give me a call at 217-333-7672.

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