Summer pruning guide: How to shape hedges and train vines

It’s a bad sign for the health of your shrubs if they are leafing out sparsely now and there is no new growth at the base. If the top of a shrub is thin and there is substantial new growth at the base, cut it back to encourage growth from the base. At some point later this summer you will need to decide whether it should be replaced depending on how the shrub looks after having more time to fill in.

Pruning is my favorite gardening task, and the summer pruning season has arrived. June and July are good months to shear and train your hedges. Prune formal hedges slightly wider at their base than at the top. This ensures that the sides of the hedge will receive equal sun exposure. It also helps to keep the foliage full from top to bottom. Many hedges in home landscapes are not pruned properly and are usually wider at the top than the base. Pruning hedges in June and July will help create a denser hedge. You can expect more growth later in the season, so plan on shearing again.

Monitor and train vines such as clematis on their supports. It is best to do this regularly to direct the vines where you want them to go. Once they have been allowed to grow out for a few weeks without support, it is difficult to train them back up. You can purchase different supports depending on the plant you are training. Twined jute works well for short-term support for small stems, while green tape is more permanent and can train larger stems. For training woody espaliers, rubber-coated wire is best.

I continue planting all summer long and see no need to wait until fall to put new plants into the ground. You do need to be more attentive to watering during the hot summer months. Make an extra effort to keep plants moist before planting to minimize stress as they can dry out quickly on a hot summer day. Containerized plants can sometimes be difficult to remoisten if they are planted when dry. Be sure that they have been watered before planting. Plants that are grown in containers have a lighter growing medium that dries more quickly than garden soil and thus needs more frequent watering until their roots go out into the surrounding soil. Newly installed balled and burlapped plants need about 1 inch of water per week to get them established. The amount and frequency of watering will vary depending on weather conditions and the soil conditions in your garden. Sandy, well-drained soils dry out more quickly than heavier clay loam soils.

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