Thoughts From Nancy
Summer came early to Michigan gardens, and hot weather and lack of rain in June has been hard on newly planted plants whose roots have not had time to become established.
Even when the rains do come, the gardens don't always get enough water to saturate the soil. Though it rained several times this last week, the total accumulation in my full-sun patch was little more than 1/10 of an inch of rain. My shade garden got even less rain because the tree's canopy of leaves act like an umbrella, so a quick shower provides little moisture. It takes a heavy downpour, or better yet a day-long rain to wet down the garden.
So if Mother Nature fails to give my garden an inch of rain I water, and when the temperatures climb into the 90s, I water twice a week.
Don't overlook your trees and shrubs when hot dry weather hits, even if they have been in the garden for many years. Rhododendrons and azaleas are shallow-rooted and suffer greatly when the soil begins to dry. Shallow-rooted Japanese maples are very sensitive to abrupt changes in the moisture level of the soil and should be carefully monitored for drought stress. Browning at the edges of their leaves indicates they are in dire need of a drink.
Some plants, such as hydrangeas, wilt when the temperatures heat up. They lose moisture through transpiration faster than their roots can take it up. So it's possible to water them well one day and find the plants wilting in the noonday sun the next. However, if the plant remains wilted in the morning, it should be watered immediately.
Soaker hoses that provide a long, slow drip are best for watering large trees and shrubs. When watering a large tree, lay one end of the soaker hose at the base of the trunk and then encircle the tree forming a spiral moving out toward the drip line. If the canopy is large, you may need to move the soaker hose to get the entire area watered.
Different types of landscape plantings require varying degrees of attention when it comes to keeping them sufficiently watered. We rarely worry much about watering a 100 foot oak tree. On the other hand, we might have to water a newly seeded lawn every day for two weeks. Each plant described in Yardener’s Helper has in its record its watering needs. We can generalize however that watering is an issue for the smallest plants and the lawns throughout the growing season, and for the shrubs and small trees only in times of drought.