When the sun is out, the Common Rock-rose, Helianthemum nummularium, shines too. In fact, it is difficult to take a decent photo of the flowers in sunny conditions because of the glaringly bright yellow. It is a plant that I associate with walking on the Mendips – a familiar sight in short turf and on exposed limestone. Unfortunately, although described as common, it is another plant that is not as widespread as it used to be. The White Rock-rose, Helianthemum apenninum, is a recognised local rarity that I finally caught flowering in profusion at Brean Down this year.
Common No Longer?
It is sad to note that such a familiar plant with Common in its vernacular name is not as common as it used to be. Helianthemum nummularium is at the south-western edge of its distribution in Somerset. It has suffered from the encroachment of scrub into its habitat. Its decline is a worry for local wildlife conservationists as quite apart from being a pretty wild flower, it is an important butterfly larval food plant.
A Somerset Rarity
The White Rock-rose, Helianthemum apenninum, is a definite Somerset rarity. It clings on in just a few sites. It stubbornly resisted Bristol University’s attempts to extend its range. I found it flowering in profusion this year on the south slope of Brean Down. It flowers a little earlier than its yellow relative. In previous years, I had arrived just a little late in the season for the best display.
Hybrid
A hybrid exists between the Common and White Rock-roses: Helianthemum x sulphureum. It is a paler yellow between its two parents. I have yet to see it. I can be patient. Maybe next year? It is such a pleasure to live in this exceptional botanical hotspot.
References and Further Reading
- Biological Records Centre (): Helianthemum nummularium. Online Atlas of the British and Irish Flora.
- Crouch, H. J. (2020): Helianthemum apenninum (L) Mill. Somerset Rare Plant Register. SRPG.
- Crouch, H. J. (2020): Helianthemum nummularium (L) Mill. Somerset Rare Plant Register. SRPG.
- Crouch, H. J. (2020): Helianthemum x sulphureum Willd. ex Schltdl. Somerset Rare Plant Register. SRPG.
- JNCC (?): Special Areas of Conservation. Habitats. Natural and Semi-natural Grassland Formations. Mendip Limestone Grasslands.
- Magnificent Meadows (?): Common Rock-rose, Helianthemum nummularium.
- Proctor, M. C. F. (): Ecological and Historical Factors in the Distributions of the British Helianthemum Species. Journal of Ecology, Vol. 46, No. 2 (Jul., 1958), pp. 349-371https://www.jstor.org/stable/2257400
- Stroh, P. A. 2015): Helianthemum apenninum (L.) Mill. White Rock-rose. Species Account. Botanical Society of Britain and Ireland.
Note
Karen does not seek or receive any commercial interest or advantage from this blog. She is not promoting any business venture. She simply loves to share fascinating facts about plants. These pages illustrate her love of plants, botany, biodiversity, gardens and creative expression. There is always so much to learn about plant diversity. This blog is designed as a showcase for photography, commentary on plants and wildlife, gardens and other places visited, horticulture and related topics. Viewpoints are her own, not those of her employer.
All above photos © Karen Andrews