April 2008

Peonies are usually reliable bloomers in the spring, but sometimes they may fail to bloom. Some possible causes for poor bloom include the following.

• Over fertilization: Will produce lots of leaves and very few flowers.
• Improper planting: Peony buds planted too deeply will produce few flowers. Peony buds should be planted 1 to 2 inches deep.
• Old plants: Although peonies will bloom for years, after 3 or 4 decades a plant may need to be divided in late summer if you have seen a gradual reduction of flowering from year to year.
• Too shady: Because peonies are so long-lived, plants originally planted in full sun may now have sun reduced because of growth of surrounding landscape plants. Pruning nearby trees may provide more sun or dividing the plants and moving them to a sunnier location will help.
• Late frost: Freezing temperatures in the spring may kill flower buds and reduce flowering. Always be prepared to cover plants in the spring when cold temperatures are predicted.

Encouraging a dense growth of grass is the best way to keep crabgrass out of your lawn. Closely mowed lawns will allow crabgrass to grow, because they tend to open up. Lawns should be mowed at 2 inches or higher to prevent crabgrass growth. Crabgrass will germinate in areas of your lawn that you are trying to reseed in the spring. The bare soil, warming spring temperatures and light frequent waterings are ideal conditions for crabgrass. The ideal time for lawn repair is late August to early September because crabgrass is dying out. If you choose to use a preemergence herbicide to prevent crabgrass germination in the spring, it should be applied before soil temperatures are greater than 55 to 60 degrees F for 7-10 days. Note that preemergence crabgrass control will kill emerging grass seedlings in areas that you may be seeding or overseeding in your lawn. The crabgrass control, Tupersan, can be applied to seeded areas. It is often combined with a starter fertilizer. In Northern Illinois, a crabgrass control application would normally occur in late April to early May. This can vary from year to year depending on our spring temperatures. Most crabgrass preemergence herbicides are combined with a lawn fertilizer allowing you to hit the crabgrass and apply your spring fertilizer application at the same time. Read and follow all label directions.

Repair dead areas in the lawn. Work up the soil well in these areas incorporating a starter fertilizer. Starter fertilizers are high in phosphorus which helps to promote root development. Sprinkle on a good seed mix of bluegrass and fescue. Rake lightly to mix seed with soil. Tamp to assure seed-soil contact. Mulch lightly with straw. Keep well watered for two to three weeks until all the seed has germinated. For our Lawn Care fact sheet series, call 773-233-0476.

Never work your soil when it is wet. Digging or tilling wet soil will compact your soil turning it into clumps as hard as concrete. It will take several seasons of adding organic matter to the soil to rebuild its structure. Use the “squeeze” test to check if your soil is dry enough to work. Take a handful of soil and squeeze it. If the soil crumbles through your fingers, you can work your soil. If it stays in a ball after squeezing, the soil is too wet to work and you should give it a few days to dry.

Don't rush the growing season. The frost–free date for Chicago is around April 25 near the lake and May 15 away from the lake. The term frost-free means that there is still a 50-50 chance of frost on the frost-free date. Be prepared for late spring frosts. Cover tender plants with row covers, cardboard, blankets, hot caps, or newspaper. Do not use metal or plastic for protection; they can conduct cold to plants. We have had frost as late as Memorial Day.

Spring is a good time for houseplant maintenance. Longer days and higher light intensity will cause indoor plants to begin growing faster. Start fertilizing again using a half strength solution every other watering. Prune hard now to stimulate new, bushier growth. Repot your houseplants when roots grow through the drainage holes, when the soil mass is filled with roots, when new leaves are smaller than usual or when the plant wilts between waterings. Plant into a pot that is one to two inches wider than the original pot.