A little maintenance keeps containers in tiptop shape

We ask a lot from annuals planted in containers. They are often tucked too close together and may not be watered often enough for their liking or, because of all the rain that has fallen this summer, had their roots soaked more than they prefer. Some annuals have thrived in the heat; others are languishing. Even with proper fertilizing, a few are just getting worn out.

This is an ideal time to revitalize containers to keep them looking their best for the rest of summer. Begin by gently removing plants that are beyond rescue. If they don't easily pull out, cut around them with a garden knife to minimize damage to roots of neighboring plants.

Next, give the remaining annuals a good cleaning. Cut back plants that have grown leggy. Petunias are a prime example of an annual that, if cut back by half, will quickly grow and flower more beautifully than its first flush of blooms.

Deadhead spent blooms. Annuals direct their energy into producing flowers and then seeds. When flowers are removed before the plant can set seeds, it begins the process again and produces more flowers. Deadheading also causes plants to branch, and more stems mean more flowers.

Cut back plants that have overgrown their allotted space. Coleus are indispensable in containers for their brilliant foliage color, but many varieties, unsatisfied with their filler role, grow tall in attempts to challenge the thriller. Sweet potato vines are another must-have annual that benefit from discipline with a pair of pruners.

Cool-season annuals looking summer worn can also be rejuvenated with severe shearing. The tiny, delicious-smelling flowers of alyssum love cool temperatures, snuggled up with pansies and violas in springtime. When summer heats up, they can be replaced with a heat-loving annual or, when their blooms succumb, sheared back by half. They'll be ready to tickle the ornamental cabbage planted for fall.

The best garden centers still have lovely plants to fill in empty spaces left behind from removing unsalvageable annuals, deadheading and prudent pruning. Cut branches from red or yellow twig dogwood can take the place of a tall annual. A small statue can be moved from the garden to a container. Imagine a concrete rabbit with million bells at its feet and geraniums behind.

Give containers, suffering from the dog days of summer, a second wind. It doesn't take a lot of time or money to keep them in tiptop shape until it is time to decorate outdoor spaces with the colors of fall.

• Diana Stoll is a horticulturist, garden writer and speaker. She blogs at gardenwithdiana.com.