Soldiers Delight, the chromium barrens

The soil here is so hostile that 39 rare species survive on it precisely because nothing common will grow.

Soldiers Delight Natural Environmental Area sits near Owings Mills in western Baltimore County, Maryland. It is designated both a Maryland Wildland, covering 1,526 acres, and a Natural Environment Area of 1,900 acres, within the Maryland Wildlands Preservation System. Its protection rests on serpentine soil and the more than 39 rare, threatened or endangered plant species living on it, along with rare insects, rocks and minerals.

Serpentine barrens are the point. The rock weathers to a soil high in magnesium and heavy metals and low in the nutrients most plants need, so the vegetation that survives is specialised, sparse and found almost nowhere else. The chromium in the name comes from the same geology.

The human history runs alongside it. Early colonial records of Maryland describe the area as a Native American hunting ground. In 1693 rangers in the King's service, patrolling from a nearby garrison, gave the land its name. In the 18th century George II made land grants to Maryland's earliest settlers in what was then Soldiers Delight Hundred. During the Civil War there were minor short-term clashes here between Maryland Volunteers of the Confederate Army and regular Union troops.

Seven miles of hiking trails are blazed across it. Pets are allowed; horses and bicycles are not, to protect the fragile ground. The visitor centre opens daily from 11am to 3pm with environmental education programmes and live animals. Bowhunting runs from mid-November to the end of January with permits and a reservation.

Maryland DNR warns that sunny days raise the temperature on the serpentine barren above the air temperature, so hiking it in heat is not recommended. Take that seriously: bare rock and thin cover mean no shade.