Sunday, October 6, 2013

Deep-watering prepares trees for summer

JUNE 2013 

Surprisingly, experts say spring is the time to prepare sidewalk trees for summer.  They advise watering them early and deep.

During DC's hot summers, city trees can bake two ways:

1) by the sun's radiation from above; and
2) by the sun's heat reflected up from the pavement, heating leaves and trunk from below.

Another problem: near the tree, the ground becomes hard and dry--a barricade against water flow. So when we're lucky enough to get rain, less rain of it reaches the important roots underground.

Enter deep-watering.

A professional water truck carries 1,000 gallons and a 100-foot hose. The hose has a "needle" that the operator pokes in the ground several times around the tree. He can turn on the high pressure water flow and change the pressure by turning the needle's handlebar, like changing speeds on a motorcycle.

Deep-watering can moisten soil  3 - 4 feet below the surface, near the big roots the tree needs to grow.

Our deep-watering project assists a tulip poplar we planted by the Embassy of Romania on Sheridan Circle.
Restore Mass Ave hired Arborcare of Rockville, Maryland to water several hundred trees along Embassy Row on June 1. (Trees to be deep-watered were marked with blue tape.) Most were sidewalk street trees; others were trees inside the sidewalk that we planted or otherwise keep an eye on. 

James Urban of Urban Tree Associates recommended deep-watering in spring as a good investment for our trees this summer. He said that though we've had much rain, the trees face hard times ahead.

Still,  EVERYONE near city trees should top-water them, 25 gallons per tree each week, all summer. And pull away grass and weeds from the tree base so hose water, rainwater and air can start their journey towards the tree's deep roots, as Nature intended.

Reminder: Only mulch LIGHTLY around trees -- experts recommend a 3-inch layer kept away from the tree base. DO NOT pile mulch against trees! "Mulch volcanoes" block air and water from reaching the deeper roots which must be nourished to grow a strong tree.

Thanks to donations, Restore Mass Ave could provide this special care. We would like to thank -- in advance -- embassies and owners who engage in follow-up care around city trees, with watering and weeding. We must work together to raise the odds that all the trees here grow big and shady.

Special thanks to RMA Board member Robert Tarasovich for managing the project.
Learn more about Jim Urban at and his Linked In page.
More about Arborcare is here. Volunteer with RMA here. Donate to RMA here.

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