This is a working draft list of locations where cactus has been found in Maryland, excluding the Eastern Shore. (Eastern Shore sites may be added later.) If you know of a location not listed here, let me know at botanybill (at) verizon.net and I will put it on the list. Also if you would like to claim a site to watch, let me know.
- Cumberland – near exit 43 on I-68.
- Flintstone – (at least three stations) – Opuntia humifusa s.s.
Anne Arundel County
- Arundel High School and Arundel Middle School – possibly mowed over –
- Global Command Antenna Field, Davidsonville – Jo Mercer
- Hancock’s Resolution – Field north of house – Not found – Extirpated
- Hancock’s Resolution – Planted in garden – Opuntia cespitosa – Chris WInton and Matt Grey
- Jug Bay, Parking Lot Meadow – Bill Harms
- Jug Bay, Sand Barrens, Parris Glendenning Area (Wayson’s Corner?) – Bill Harms (More info)
- Jug Bay, South Farm
- Milt’s Sand Pit, Sands Road – large population – old field – Opuntia humifusa – Bill Harms – (More info)
- Patuxent Research Refuge, Lake Allen – large population – Opuntia cespitosa with some putative introgression with Opuntia humifusa – Bill Harms (More info)
- Patuxent Research Refuge, East of Tipton Field – likely planted many years ago – >Opuntia cespitosa – with some putative introgression with Opuntia humifusa – Bill Harms
- Sandy Point State Park – Extirpated?
- Weinberg Park – Opuntia humifusa s.s. – probably planted
- Wooton’s Landing – assumed to be planted in two stations. Not found June 2019 – Possibly removed.
- Cromwell Valley Park
- Factory Road – planted possibly from nearby wild stock – Opuntia cespitosa. (More info)
- Phoenix area – collected in 1986
- Broome Island
- Flag Ponds
- Chapman State Park
- East of Emmitsburg
- Main Street, Elkridge – Planted next to a parking lot – Opuntia humifusa s.s. (more info)
- Bear Island
- Southern end of the Billy Goat A Trail in C&O Canal NHP
- Plummer’s Island – Extirpated
- River Road, SSW of Poolesville – Confirmed as Opuntia humifusa – Robert Ferraro
Prince George’s County
- Billingsley House
- MacGruder’s Landing
- Nottingham Road – apparently planted – tentatively Opuntia mesacantha ssp. mesacantha
- Priest Bridge
- Queen Anne Canoe Launch – open meadow – apparently Opuntia humifusa s.s.
- Rte 301 – small number of plants – planted
- Commander’s residence USN Solomon’s Recreation Area in Lawn
- Patuxent Naval Air Station, East side of Security Road at NE corner air station.
- Piney Point
- Kemps Mill – None found on a re-visit to area with Joe Metzger in 2018. Possibly extirpated.