General Guide

Trees need water, good soil and space to root.

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Watering Street Trees

You should give a new street tree 20 gallons of water once a week, or run a low-pressure hose at the base of the tree for 20 minutes. A tree needs about 10 gallons of water per inch of trunk diameter. Boston’s new street trees are typically two inches in thickness.

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During really hot weather, a tree will need 30 gallons of water each week in two separate waterings: 15 gallons one day and 15 gallons a few days later.

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Tips for pouring the water:

• Please pour slowly at the base of the tree and in the tree pit.

• Cultivating or digging up the top three inches of the pit can help the water get to where it needs to go.

• A three-inch layer of mulch will help the soil stay moist and prevent weeds.

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Mulching Street Trees

You can add a three-inch layer of loose, coarse mulch at least three inches from the tree trunk. However, mulching the wrong way can lead to several tree problems:

• root rot (soil becomes waterlogged, leading to low levels of oxygen)

• disease (deep, moist layers of mulch attract diseases and insects)

• water stress (a thick layer of mulch can stop the flow of water to the root)

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Please read “Mulch Out, Not Up” for more information.

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