Trees growing along city sidewalks have such small openings in which to grow. Can enough rain really get through the openings to keep trees alive, or is some water soaking through the concrete?
— Jennifer, Medford
While some urban street trees are kept alive by hidden drip irrigation systems, many rely on the kindness of strangers — or at least nearby property owners, according to Ashland Parks and Recreation Landscape Division Manager Anne Thayer.
Rain doesn't permeate concrete sidewalks, but some can get through asphalt, which is semi-porous, she said.
New trends in sustainable construction call for using permeable materials, such as pavers, to allow water to percolate into the soil, Thayer said.
While downtown Ashland street trees are kept alive through irrigation systems, Thayer said homeowners are usually responsible for keeping street trees alive in front of their houses in subdivisions.
If the trees aren't reached by irrigation systems, she recommends using a soaker hose once every week or two to slowly and deeply water trees, which have roots extending far underground. If you can't get a hose to the tree, another option is to puncture the bottom of a 5-gallon bucket, fill the bucket a few times, each time allowing it to slowly drain into the soil surrounding the tree.
Southern Oregon doesn't receive enough precipitation to keep most street trees alive without additional watering, she said.
"Street trees do require irrigation to survive," Thayer said.
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