Pull weeds when soil is moist for best root removal

At this time of year, regular weeding is important. Some plants, such as dandelions and chickweed, are easily identified as weeds, but my definition of a weed is any plant that is out of place.

If you pull weeds when the soil is moist, the roots come out more easily. A small hand weeder or trowel is helpful in getting the entire root, especially on weeds with deep taproots such as dandelions and plantain. It's very important to get weeds out before they go to seed.

Look for tree seedlings such as buckthorn, mulberry and box elder that tend to establish themselves in hedges and in the base of shrubs. Look closely and they are easy to spot. In areas where it is not practical to dig out the roots of these weed trees, treat the stumps with an herbicide containing glyphosate promptly after cutting to kill the root system.

Trees planted in lawns can benefit from a wide ring of mulch 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 - the outer edge of the tree's crown of branches, where rain drips from the leaves.

If the tree is too large for this to be feasible, extend the mulch as far as you can. Even a 6-inch-wide ring of mulch will help protect tree trunks from serious damage.

Do not mound mulch or soil around trunks, because it is unattractive and can cause rotting at the base of the tree.

Groom your perennial borders to improve plant appearance and maximize flower production.

Gently remove dried or yellowed bulb foliage when it starts to yellow, since the bulbs are going dormant and have already stored nutrients for next year's flowers.

Deadhead, or prune off spent flowers, on your annuals and perennials to encourage them to continue flowering. Remove any yellow leaves to keep the plants neat and tidy.

Prune out water sprouts (vigorous shoots on the inside a tree or on the trunk) and suckers (shoots growing from the base of a tree). Crabapples and hawthorns tend to send out lots of water sprouts and can benefit from this type of pruning.

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