Look around for changes that require extra care

One of the most important parts of gardening is observing changes in your plants and knowing how to adjust care for them. Recently, I noticed annuals that were stunted with yellowing foliage. Because the gardener said she had been watering enough, I suggested they needed fertilizer. Keeping annuals too dry can also stunt growth.

Cicadas have been busy laying eggs, so damage to trees is becoming visible. I was surprised to see some evidence of egg laying on a hydrangea shrub. Look for slits in the bark on the undersides of stems. Generally, the damage caused by cicadas is nothing to be concerned about.

Mulch ring can protect trees

Trees planted in lawns can benefit from a mulched ring to reduce competition with grass roots and keep mowers and weed whips from damaging trunks.

If the tree is small, mulch out to the drip line, which is the outer point at which rain drips off the foliage of your tree. If this is not feasible, extend the mulch as far as you can while keeping the size of the mulched saucer in scale with the surrounding landscape. Even a 6-inch-wide mulched saucer will help protect tree trunks from serious damage.

Do not mound mulch or soil around trunks (known as volcano mulching), because it can contribute to stress on the tree and impact its health.

Time for a trim

Groom your borders to improve plant appearance and maximize flower production. Gently remove dried or yellowed bulb foliage if you have not done so yet, since the bulbs should be mostly dormant by now and should have already stored nutrients for next year’s flowers. Deadheading — or pruning off spent flowers on annuals and perennials — encourages them to continue flowering. Remove yellow foliage to keep the plants neat and tidy.

Cutting flowers for display

This is a good time to cut outdoor flowers for indoor display. It is best to cut flowers during a cool part of the day and to put them in water as quickly as possible. Remove any foliage that will be under water in the vase. Keep arrangements in a cool room out of direct sunlight. Adding a preservative to the water can lengthen the life of the arrangement.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.