Watering New Trees and Shrubs

Planting a shrub, Photo by John Fech

Many new trees and shrubs are planted in April, May and June.  By far, the two most important considerations are implementing the proper techniques for planting and watering.

Perhaps the most overlooked part of tree/shrub planting is the need to dig a wide and shallow hole; the good news is that it’s really easy as illustrated in the photo.  Simply remove enough soil to equal 2-3 times the root mass of the new plant on each side of the hole, but no deeper.  Then, tease out the circled roots that have been created by the pot the tree was growing in at the nursery, and place it in the center of the hole.  Next, use a small shovel to add the excavated soil back around the roots, watering lightly after every 2 shovelfuls.  Avoid replacing the original soil with any soil amendments such as compost, peat moss, topsoil or potting soil.  Using these products creates a condition where the roots will preferentially stay in the hole instead of growing outward into the landscape.

After planting, use a sprinkling can to finish off the soaking and settling of the soil.  For most trees and shrubs, 2 gallons of water, applied lightly and slowly will get the plant off to a good start.  After the initial thorough soaking, avoid watering again for 5-7 days.  Use a soil probe such as a piece of rebar or long screwdriver to test for soil moisture in the root zone after a few days; this is important as some soils retain moisture longer than others.  If the blade of the probe is dry and powdery after you pull it out, then it’s time to water again.  If it’s cool and moist, wait a couple of days and retest.  The desirable moisture level is just that – moist, not soggy or dry.  Soggy conditions lead to root rot, while dry conditions lead to dry roots; either usually results in tree/shrub death.

Drip irrigation devices are convenient and efficient devices to water new trees and shrubs after planting.  Many types are available as shown in the photos.

sprinkler hose setup   A sprinkler hose near a tree base   final landscaping, with the sprinkler head hidden by shrubs

This article was reviewed by Nicole Stoner

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