Capitol Hill Restoration Society

Tree Space Beautification

Posted on January 2nd, 2017

CHRS encourages residents to adhere to these best practices (summarized from the District guidelines), which will contribute to the robust growth and general health of Capitol Hill’s public space trees.

District regulations regarding Tree Space Beautification (in ,pdf format)

Tree Space Beautification Best Practices (in .pdf format):

Tree Space Beautification Do’s and Don’ts
Do Don’t
Adding soil amendments or replacing some soil in a tree space prior to tree planting should be done in consultation with a DDOT arborist.  After planting, adding only mulch and periodic light cultivation is advised. Never try to replace soil around a tree after it has been planted.  Trying to replace soil around a tree usually results in a dead tree within 1 or 2 years – particularly for trees that are just becoming established.
Mulching around a tree is encouraged, as is watering new trees when rainfall is less than 1 inch per week.  New trees need 10 to 20 gallons of water once a week from spring bloom until winter freeze.  Second and third year trees need up to 20 to 40 gallons/week. Using gravel as a groundcover or depositing soil to increase the grade of a tree space is prohibited (24 DCMR 109.7).  Piling on additional soil exposes the tree bark to soil borne diseases and robs the roots of Oxygen.
Any temporary barrier or fencing must allow the free flow of rain water from the sidewalk into the tree space. This applies to permanent tree fences too. DDOT requires a permit to plant a tree or to install a permanent tree fence or structure in a tree space (24 DCMR 109.3). Don’t install any solid border or edging around a tree space.  This practice prevents or impedes the flow of rain water from the sidewalk into the tree space.  DDOT has been enlarging tree spaces in an effort to increase the amount of rainwater runoff available to trees.
Limit plantings to annual or perennial plants having a shallow root system and a mature height of no more than 18 inches tall. Don’t use plants having a deep root system, that spread by underground shoots or runners, that climb or intertwine, or that are invasive.
Acceptable plants include perennials such as variegated Liriope, Ferns, Hostas, Dusty Miller, Yarrow, Sedums, Black-Eyed Susan, and flowering annuals that grow no more than 18 inches tall.  Plants should be at least 2 feet from the tree trunk. Don’t plant bamboos and dark green Liriope, which spread by underground shoots to form an impenetrable root layer, or English Ivy which climbs.  Vegetable plants are not flowers and are prohibited (24 DCMR 109.11).