Wise summertime watering of trees, plants and lawns
Garden writer Ciscoe Morris explains how to save trees from drought stress and gives tips on summertime watering, including grouping plants according to their watering needs and mulching to reduce evaporation.
Special to The Seattle Times
Fall Containers for Sun or Shade: 10 a.m. Aug. 23. Master gardener Frani Gallwas will give tips and suggestions on how to build a fall container. Free; register online or call 253-863-5843. Windmill Gardens Nursery, 16009 60th St. E., Sumner (www.windmillgarden.com/windmill_events).
Summer Fest: 10 a.m.-3 p.m. Aug. 23. Tours, raffle, book signing, arts and crafts for kids. Hume’s Children/Educational Garden, 11504 58th Ave. E., Puyallup; free, donations of nonperishable goods for Puyallup Food Bank welcome (www.humeseeds.com/edgarden.htm).
Puget Sound Dahlia Association Show: 9 a.m.-6 p.m. Aug. 23 and 9 a.m.-4 p.m. Aug. 24. Sky Nursery, 18528 Aurora Ave. N., Shoreline; free (www.skynursery.com/puget-sound-dahlia-association-show).
In the Garden
Many of us stop watering our lawns during summer allowing the grass to go dormant. It’s not a problem for the lawn because the grass will green back up when the rains return in fall, but the same cannot be said for the tree growing in or next to that dormant lawn.
Trees remain actively growing in the heat of summer, and the vast majority of a tree’s roots, even those of very large trees, are located within the top 6 to 24 inches of the soil. Often the roots of lawn trees are found just below the surface of the grass where soil can become bone-dry if the lawn isn’t watered.
To prevent drought stress that can lead to increased susceptibility to insect and disease problems, be sure that the tree receives a deep watering once per month. In the absence of summer rains, wrap the tree with a soaker hose working your way out from the trunk in concentric circles, ending as close as possible to the drip line (end of the canopy).
Run the soaker for a couple of hours, then dig a test hole if the water penetrated a foot deep, and run the soaker longer if necessary. Take it from Cass Turnbull, president and founder of Plant Amnesty, an organization dedicated to the proper care of woody plants: Water is expensive, but not nearly as expensive as replacing your trees and shrubs.
Make every drop count
Here in the Puget Sound region, we experience some of the driest summer weather in the nation. On average we receive only about 7 inches of rain all summer long. When you compare that amount with the average precipitation of around 20 inches during the same time period in my native Wischeescin, it becomes obvious that watering is an absolute necessity if you want to grow a variety of plants.
At the same time, it’s important to water properly so we don’t waste this valuable resource. One of the best practices to ease effective watering is to group plants according to their water needs. This allows you to provide ample water to those that require it while preventing root rot caused by overwatering drought-tolerant plants.
At least once a year, apply at least an inch-thick layer of organic mulch over the soil surface. Mulch cools the soil surface, reducing evaporation and holds water, thereby reducing runoff while increasing absorption.
Whenever possible, water early in the cool of the morning to minimize evaporation while allowing leaves to dry quickly to help reduce disease problems. Where practical, use soaker hoses to water vegetable gardens and shrub beds. When using overhead sprinklers, adjust the settings to water only the bed or lawn rather than the sidewalk.
Finally, remember that even in hot, dry weather, lawns and garden beds generally need only 1 inch of water per week. To figure out how long to run your sprinkler to apply 1 inch of water, mark a 1-inch line on a number of tuna cans or similar containers and place them around the lawn and/or garden beds. Run your sprinkler and time how long it takes to fill the majority of the containers to the 1-inch mark.
It’s better to water deeply and infrequently, so apply the inch of water in one or, at most, two applications per week.
Ciscoe Morris: firstname.lastname@example.org “Gardening With Ciscoe” airs at 10 a.m. Saturdays on KING 5.
About Ciscoe Morris
Ciscoe Morris' column runs Thursdays. His show "Gardening with Ciscoe" airs at 10 a.m. on Saturdays on King 5.