Don’t assume that your sprinkler system is providing the right amount of water. Monitoring the plants and the soil moisture will help you provide the optimum amount of water for your garden plants. (RJ Carlson/Chicago Botanic Garden)

“Is it too late to install a new garden this year? And should I be watering other plants in my garden?”

You can continue planting all summer, providing you pay close attention to watering. I have been seeing new garden installations struggling because of improper watering in some gardens recently. Most of the plants under stress were ones grown in containers, and will dry out quickly in hot and windy weather.

It’s difficult to give you specific instructions for watering, as there are many variables based on a garden’s growing conditions. Gardens with sandy and well-drained soils will need more frequent watering to get the plants established, as the soil will dry out more quickly than a heavier clay soil. Different types of plants prefer different levels of moisture. Perennials planted in a shady zone may be competing with tree roots for water. The amount of sun or shade will influence how much water is needed for those areas. Different zones may dry out at different rates.

The established plants that have been growing for over three years probably do not need supplemental watering now. Plants that have been more recently installed over the last two to three years can benefit from supplemental water this year during dry periods. Any plants installed last year and this spring should get priority attention.

I just watered some hydrangeas that I had planted in fall of 2020 after seeing them wilting. Wilting foliage is a signal to check if that plant needs to be watered. The hydrangeas are planted under an oak tree so they are competing with the tree and surrounding perennials for water, and even though the bed is shaded, it dries out quickly.

Check the soil at the base of your plants to see how much moisture is present to guide you in determining whether to water. Plants show water stress with wilting foliage and foliage that turns an off color of green or yellow to brown when dry. Water trees and shrubs that were planted as balled and burlapped trees with a hose at the base to thoroughly moisten the root balls during the first one to two years of establishment.

You should not rely solely on a sprinkler system. Even recently installed perennials will benefit from an occasional deeper soak with a hose while they are getting established in their first year. The foliage of evergreens can shed water from a sprinkler to the outside of the root ball, leaving it dry. As the tree establishes over the first two to three years, the roots will grow out into the surrounding garden soil. Generally, one thorough watering a week will suffice for new balled and burlapped plants during the first year.

Also monitor to make sure you are not overwatering, as I have seen gardens with soggy soil even during dry periods — a sign of overwatering, which can also stress and kill plants. Plants that were grown in containers may need to be watered a couple times a week when the weather is hot and dry for the first few weeks after planting. As the plants root out into the surrounding garden soil, they will dry out less quickly. In any case, check them a couple times a week after planting.

If you are using an automatic sprinkler system or watering with a sprinkler attached to a hose, check that all the plants are getting adequate water by monitoring the soil and spot checking the plants’ root balls. Don’t assume that your sprinkler system is providing the right amount of water. Monitoring the plants and the soil moisture will help you provide the optimum amount of water for your new garden plants.

Proper watering is critical to having success with seeding a lawn, and I see many gardeners fail at this. The grass seed needs to be kept moist with frequent, light watering of one to three times per day until it germinates in approximately two weeks. Letting it dry out during this time can dramatically reduce germination of the seed. A light layer of compost can help retain moisture for the grass seed.

For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.