Garden staff adds new plants throughout the summer

Monitor any new plants that have been installed over the last couple of years to assess their watering needs. Conditions have become drier after a very rainy spring, and recent rains may not have been enough to adequately water the newer and less established plants.

More established plants in dry shade, such as my Annabel hydrangeas growing under an oak tree, may also benefit from some supplemental water in order to get the best performance.

• It is fine to continue planting at this time of year. The Chicago Botanic Garden staff installs new plants all summer long. The key to success with planting in the heat of summer is to pay close attention to watering of the new plants.

• It is better to cut your lawn at a height of at least 3 inches during the heat of summer as it will be better able to withstand these environmental stresses. Stronger growing turf will help choke out weeds.

A tall cutting height is less important if you are regularly watering your turf all summer long. I do not water my lawn, and it has started to go dormant and does not require a weekly mowing.

• Coleus can slowly overtake and choke out adjacent plants in a container or bed. Simply pinch them back to control their size and thicken up the plants.

• Thistles are a very difficult to eradicate from the garden so it is very important to pull them or at least cut them back before they go to seed. It is difficult to get the roots out.

If you have a patch that has gone to seed, then it is best to carefully remove the seed heads before pulling them to avoid spreading the seeds around. Put the seed heads in the garbage.

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