Give plants a midsummer's sprucing

Published on July 1, 2009

by Jo Ellen Meyers Sharp

Most of the cool season annuals, such as pansies and lobelias, can be thanked for their service and yanked out or cut back to the ground. Only in the coolest regions of the country will these plants continue to flourish. In the Midwest, we replace these annuals with heat lovers, such as salvia, zinnia and moss rose, which will bloom well into fall before being claimed by frost or freezes.

However, some spring-blooming perennials can be tricked into blooming again. A plant's sole purpose is propagation. Deadheading, or removing the spent flowers, fools the plants into thinking they need to keep flowering to produce the seeds that reside inside the blooms. Cutting back perennials and many annuals about halfway this time of year also improves the shape of the plants, their branching and flowering. It usually takes a couple of weeks for plants to begin flowering once given a trim.

Removing the top 2- to 6-inches from summer-blooming perennials can be critical for Southern gardeners, where hot days and warmer than average nights can zap the energy from people and plants. Cutting back the top growth reduces the amount of leaves and flowers a plant has to support, allowing it to rest a bit before resuming its blooms.

Although New York City doesn't usually have sustained periods of 100-degree days, gardening on rooftops and balconies can be brutal. For the past 12 years, Ellen Zachos, owner of Acme Plant Stuff, has planted and tended hundreds of containers for her Manhattan clients and says, "If you can garden here, you can garden anywhere."

Plant selection and irrigation are the keys to successful container gardening in urban environments. Long-blooming, hot-weather loving perennials paired with annuals that have the same requirements can go a long way to keeping containers looking their best.

Zachos also advocates cutting back annuals or perennials, but maybe even more important is making sure plants get adequate moisture, and she encourages her clients to install drip-irrigation systems for their pots.

Sometimes the soil in containers become hydrophobic, a condition where water sits on the soil surface or runs straight through without being absorbed. When that happens, she suggests plopping a tray of ice on the soil surface, making sure the cubes do not touch the plants. As the ice melts slowly the soil is able to take up the moisture. Another alternative is to place a container in a shallow pan of water and allow the soil to take up the moisture. Remove from the pan when the soil surface feels moist.

Sometimes known as the Hoosier Gardener, Jo Ellen Meyers Sharp lives in Indianapolis and is part owner and editor of Indiana Living Green magazine. Her work has also appeared in many other publications, including The American Gardener, Garden Gate and Greenhouse Grower. In addition, Meyers Sharp speaks about gardening and sustainable living throughout the Midwest and is a director of the Garden Writers Association.