When it comes to trees and shrubs, water deep

“Maybe I should but how much do I need to?” “Maybe it will rain but will that be good enough?” “I’ve thought about it but when is the best time to do it?”

Now that the summer heat has set in and the soil is getting rather dry, many gardeners are asking: ” Should I be watering?”

The answer: Yes!

All trees and shrubs that were planted within the past two years, lawns that were seeded or sodded last fall or this spring, shallow-rooted perennials and ornamental grasses should all be watered. The sunny days combined with hot winds have dried out the soil. Even though plants may look healthy and green, the roots are having a hard time finding water and nutrients.

And I think it is safe to say that the little rainfall that we have received recently is not enough.

So what is the best method of watering? The answer is best stated by two words: Water deep.

For newly planted trees and shrubs, turn the hose on and let it trickle at the base of the plant. Thoroughly soak the root ball and surrounding soil. A safe amount to apply is about 5 gallons of water per inch of tree trunk diameter. So, a tree that’s 3 inches in diameter needs about 15 gallons of water applied slowly over the root ball.

For the lawn, apply 1 inch of water as needed. One inch of water will effectively soak to a depth of 6 inches into the soil. This is where most of the roots are growing. If watering perennials and ornamental grasses, there are no magic amounts however, do not be stingy.

Although this spring was cool and moist, last summer, fall and winter were hot and dry. The result is little subsurface moisture. And once the surface moisture is lost, roots will quickly run out of water. To help ensure that your landscape plants and lawn survive this summer, it is a good idea to give them a drink.


Bruce Chladny is horticulture agent at K-State Research and Extension-Douglas County. For more information, call him at 843-7058 from 8 a.m. to 5 p.m. weekdays.