We’ve listed a couple of hotel recommendations that are close to the National Arboretum (<10 minutes by car), and there appear to be plenty of good Airbnb options as well.
Hotel
Homewood Suites by Hilton Washington DC NoMa Union Station
501 New York Avenue Northeast Washington, DC 20002 (202) 393-8001
Hotel
Hampton Inn Washington DC NoMa Union Station
501 New York Avenue Northeast Washington, DC 20002 (202) 393-1001