Shrubs can be trained to lay flat against a wall

Espaliered plants are used for softening large blank spaces on walls or fences. To train espaliers, twigs and branches are bent to meet design requirements when they are young and supple. Carefully tie the branches in place with raffia or plastic tape.

The ties should be secured loosely so the flow of water and nutrients through the stem is not constricted. Make adjustments to ties during the remainder of the growing season as necessary. These types of espaliers will need routine pruning throughout the summer to look their best.

• My definition of a weed is a plant that is out of place. A good time to weed is when the soil is moist - the roots come out more easily.

It's very important to get weeds out before they go to seed. A small hand weeder or trowel is helpful. 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 stump with glyphosate promptly after cutting to kill the root system.

• Groom your borders to improve plant appearance and maximize flower production. Gently remove dried or yellowed bulb foliage since the bulbs are going dormant and have already stored nutrients for next year's flowers.

Prune off spent flowers (deadhead) on your annuals and perennials to encourage them to continue flowering. Remove yellow foliage to keep the plants neat and tidy.

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