D.C. Code § 8-302
Whenever there are upon any unoccupied land aforesaid weeds of 4 or more inches in height, and no person can be found in the District of Columbia who either is or claims to be the owner thereof, or who either represents or claims to represent such owner as aforesaid, the Mayor of the District of Columbia shall give notice, by publication twice a week in 1 daily newspaper published in the City of Washington aforesaid, requiring their removal. Said notice shall specify the land from which such weeds are to be removed, the character of the work to be done, and the time allowed for doing the same; and if such weeds be not removed within the time so specified it shall be the duty of said Mayor to cause their removal; and double the cost of such removal, including the cost of advertising, shall be a lien upon and shall be assessed by said Mayor as a tax against the property on which said weeds were located, and the said tax so assessed shall bear interest at the rate of 20 per centum per annum till paid, and shall be carried on the regular tax rolls of said District and be collected in the manner provided for the collection of general taxes.
D.C. Code § 8-302