Gardening: Time to take stock of annuals, perennials

Nanzy Szerlag
Special to The Detroit News

With temperatures finally cooling down, many gardeners are taking stock of their gardens. The hot, dry weather was tough on flowering plants this summer, especially perennials. Their bloom times were shortened in the heat, and leaves are looking ragged.

The knee-jerk reaction for many gardeners is to fertilize them, but that may do more harm than good.

For most perennials the big show is over, so the plants’ need for nutrients is lessened and hosing them down with a so-called “liquid feed” or sprinkling the soil with dry fertilizer will only stress them further. Dousing these plants with fertilizer in August will stimulate them to produce new leaf growth in fall when the plants should be storing carbohydrate reserves for use in spring when they emerge leafless from the soil.

A quarter-inch layer of quality compost, such as Organimax, layered on the surface of the soil around perennial plants and covered with a couple of inches of shredded leaves in fall provides about all the nutrients most perennials need for the year.

Annual plants, on the other hand, have a couple more months of work ahead of them before they meet their great reward on the compost pile, so weekly fertilizing with a water-soluble product at half strength will keep the show going. Organic gardeners may prefer to use fish emulsion, such as Neptune’s Harvest Fish and Kelp formula.

Petunias that look straggly can be rejuvenated by pinching them back. A Google search on “how to pinch back petunias” will result in several videos that show just how this is done and will give you the courage to get out the scissors and have at them.

August is also a good time to begin planning next year’s garden design. Plants that failed to meet expectations may need to be moved to new locations that better meet their needs or dropped from next spring’s shopping list.

If you’re looking for something special, early September is the time to give your wish list to the head grower at your local nursery or garden center that grows plants. That’s the time they place orders for seeds and cuttings. Wait until next spring to find your heart’s desire and you may come up short.

Pictures are worth a thousand words and your camera, smart phone or iPad will become your best friend when planning next year’s garden. And be sure to take pictures of combinations or plants that did not work as well as your successes.

Nancy Szerlag is a master gardener and Metro Detroit freelance writer. Her column appears Fridays in Homestyle. To ask her a question go to and click on Ask Nancy. You can also read her previous columns at