Magnesian Limestone rocks are an interesting feature of the North East’s geology, with the resulting mineral-rich soil giving rise to some unique wildflowers that can be explored here.
Magnesian Limestone, often called Dolomite, was originally formed in the shallow tropical Zechstein Sea some 250 million years ago, and now outcrops in only a few places in the Northeast of England. The limestone weathers to form thin, lime-rich soils, the specific composition of which allows the growth of unique wildflower meadows native to the North East.
Typically, such limestone grassland areas support scarce plant species, including blue moor grass, small scabious, rock-rose and dark red helleborine to name but a few. Insects abound with many unusual species present. Two notable examples are the salmacis form of the northern Brown-Argus butterfly and the glow-worm, visible in the wild for limited periods over the summer.
In the Botanic Garden, we have aimed to reproduce this regional curiosity with our own Magnesian Limestone habitat. This bed was created in 2005 to showcase some of the wildflowers that can be found among the several Magnesian Limestone areas in the North East. Twenty tonnes of large boulders were used to build a raised bed adjacent to a footpath for easy viewing. The wildflowers are at their best in early July, but the real gems are the local Magnesian limestone meadows, some only a few miles from Durham, which are well worth a visit.