Common and White Rock-roses

Eye-catching Common Rock-rose, Helianthemum nummularium

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.

Glaring yellow in bright sunshine of Common Rock-rose, Helianthemum nummularium. Note the creeping, woody appearance and visible leaves in this shot.

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.

White Rock-rose, Helianthemum appeninum flowering at Brean Down, Somerset in 2021
Single White Rock-rose, Helianthemum apenninum, seen in flower at end of its season in evening light


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


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

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