Water Young Trees in Summer

If you planted a tree within the last two or three years (congratulations!!!), it is still in the vulnerable stage of early root growth. Young trees need to be watered once a week, or twice a week if the weather is especially hot and dry.  The amount of water needed depends on a variety of factors including tree size and how well the soil drains.  Here are the watering guidelines in my area, from the Arlington County, VA website: 

Trees planted within the past two years that are less than 6 feet tall need a minimum of 5 gallons for each watering.  These trees should be watered at least twice a week starting in April and continuing through November.  Rainfall should not be considered adequate unless it is 2" or greater. 

The best time of day to water is early in the morning so that the amount of evaporation is minimized.  Late in the evening is the second best time.  The amount of water that comes through a hose varies for a variety of reasons such as hose size, length, size of the building's plumbing, water pressure, etc.  However, you can still estimate that about two gallons of water flow through a typical garden hose per minute.  This is roughly comparable to the amount of water that flows through the typical shower. Therefore, you should water newly planted trees for at least (3) three minutes with an unrestricted hose.  Hoses with sprinklers may need to be run longer since sprinklers may restrict the amount of water that flows each minute.

Casey Trees of Washington DC recommends "25 to Stay Alive", meaning 25 gallons per week, but the amount of water needed each week depends on the local precipitation and temperature. During the summer months, Casey Trees posts weekly tree watering recommendations on the main page of their website. Check it if you‘re unsure how much water your trees need. You can also sign up to follow them on Twitter, and that way you can receive reminders to water your trees.  If you don't live in the National Capital region, look for tree advocacy organizations in your area for information on the specific needs of the trees in your ecological region.

If you use a slow-release watering bag such as a  Treegator or an Ooze Tube, re-fill it each week from May to November.  These bags should be removed after two years. Arlington County, VA has a water truck and staff dedicated to watering street and park trees during the summer.  However, if you are within hose-watering distance of public trees that appear to be in distress, consider doing the trees and the community a favor and give the trees a drink. The watering bags can be tricky, so go ahead and visit the Treegator website for instructions. My neighbor Cheryl was motivated to fill the Treegator on the county street tree in front of her home, but it was so confusing that she wrote an article about it for our neighborhood newsletter to show others how to do it after she figured it out. Here's a link to her article, "Solving the Water Bag Mystery," in our civic association newsletter (hint, it's on page 8).

For more information on tree care, visit the TreeStewards website. Also, check out some of the great links over there to the right, such as the Tree Owner's Manual, a free downloadable, printable book from the USDA Forest Service, with everything you need to know about planting and caring for trees. =>