Badgeworth near Cheltenham was once the smallest nature reserve in the country, a designation now held by Hethel Old Thorn in Norfolk which contains a single tree, area 0.06 acres. The Badgeworth reserve, 2.4 acres, was enlarged sometime after its creation (in 1933) by addition of two fields underlain by clayish soils, adjoining the main feature; a shallow overgrown pond which is one of only two UK locations for the adder's-tongue spearwort, a very rare member of the buttercup family, though one much more common elsewhere in the world, growing across Europe, North Africa and Asia. The other UK location is Inglestone Common, near Yate.
Partly to protect the plants and partly as the site is not so special for most of the time, when the wildflowers are not blooming, the reserve is only open to the public on one day a year, in early June, though it is guarded merely by a locked gate and a low fence. On the open day people from Gloucestershire Wildlife Trust are on hand to guide visitors and answer questions. Most of the other aquatic plants are also in bloom at this time.
Badgeworth Nature Reserve lies close to the suburbs of Cheltenham, on the southwest side, along a quiet road, Cold Pool Lane (named after the pond), 2 miles from M5 junction 11. There is no designated parking though vehicles can be left on a grassy verge opposite the entrance, shortly before a farm building. From the gate and GWT notice, a narrow path crosses the northernmost of the two pasture fields, neither of which seems to contain any notable plants, while the main path, a short, wooden boardwalk, leads around three sides of the pond, which is partly shielded by trees and is deepest, still just a few inches, on the west side where most of the spearwort grows. The pond is also a favoured site for amphibians, with frogs and three species of newt (palmate, great crested, smooth) recorded here, plus over 300 types of beetle.