Spotlight on some special pavement plants

Protected plants

Schedule 8 of the Wildlife and Countryside Act 1981, which is revised every five years, provides a list of protected plants. It states that it is “unlawful to intentionally pick, uproot or destroy the wild plant or any seed or spore attached to the wild plant.” Council officers should familiarise themselves with these plants and make sure they are not removing these rare species, further depleting the UK’s biodiversity. Find the list here9 .

Rare or not so rare? That’s the question for Jersey Cudweed (Gnaphalium luteoalbum)

Could Rue-leaved Saxifrage (Saxifraga tridactylites) be the plant equivalent of the urban Peregrine Falcon?

Peregrine Falcons, birds of our wild cliffs and rocky coasts, have found the conditions to thrive on church towers and blocks of flats where there’s an abundance of nesting sites and prey birds. Tiny Rue-leaved Saxifrage is a plant of sand-dunes and limestone rocks but, like the Peregrine, has found similar urban conditions to its natural habitat in which it can thrive.

For this plant, the dry and lime-rich substrates where competition from other plants is limited, are replicated on city walls built with lime mortar, railway tracks and cobbles. It is recorded across Central London, in particular along the Thames wall in Southwark, and is increasingly recorded in urban areas across lowland Britain.

While many of our native flowers are under threat through habitat loss, there are a small number which are bucking the trend.

Jersey Cudweed is an annual in the Daisy family. It grows up to 45 cm tall with a cluster of inconspicuous red-tinged flowering heads surrounded by thin strawyellow bracts. The stem and oblong leaves are covered with white woolly hairs.

This flower is native to Jersey, Norfolk and Kent where it is usually found in sandy fields, on dune slacks or on waste land. In these dry habitats the woolly hairs probably help reduce water loss. Jersey Cudweed is reported as “very rare” in the popular 2016 Collins Wild Flower Guide and has added legislative protection against being removed.

Visit South East London today and you’ll see that “very rare” Jersey Cudweed is actually thriving but the legislation hasn’t quite caught up. These urban plants, usually on the small side, are well-adapted to dry conditions and can be found carpeting paved driveways, pavement edges and on urban walls. Outside of London, there are records in Cambridge, Southampton, Ipswich, Manchester, Nottingham and Dublin too.

Up to 10 cm high, the plant has fleshy “three-fingered” leaves, as its common and Latin names suggest, and is covered with red glandular hairs giving it an overall reddish appearance. It flowers from April to June producing attractive white flowers.

Oxford Ragwort grows naturally on the volcanic gravel of Mount Etna in Sicily and the story of how this pioneer became a common urban plant in the British Isles is told brilliantly in Richard Mabey’s 2012 book Weeds. Mabey writes that it was first spotted in Oxford Botanic Garden in the 18th century, then escaped the Garden, spreading along the city’s ancient walls in which the cracks perhaps mimicked hardened lava, and reached Oxford rail station by the 1830s. With its fluffy seeds reportedly filling carriages, it had reached London by 1867 and went on to arrive in North Devon, Suffolk, Kent, Somerset and Herefordshire by 1899. By 1915 it had travelled as far as the Clyde in the north and Caernarvon in the west and by WW2, it was the third most recorded weed in botanist Edward Salisbury’s survey of bombsite plants.

This annual or short-lived perennial in the Daisy family grows up to 50 cm tall and could be confused with its relative, Common Ragwort, as they both have lobed leaves and yellow daisy-like flowering heads. It’s distinguished by its more loosely grouped flowering heads and consistently black-tipped bracts surrounding them.

This extraordinary traveller is now common on pavement edges and in urban tree pits, and like other ragworts, attracts insects like hoverflies, bees and moths, particularly in late autumn and early spring when there are few other plants in flower.

Are ‘weeds’ valuable to pollinators?

In a recent study10, University of Sussex researchers compared the biodiversity value of plant species classified as ‘injurious weeds’ by the 1959 Weeds Act11 with the species promoted by the Department for Environment, Food and Rural Affairs (DEFRA) as being preferred by pollinators.

They found that the abundance and diversity of pollinators visiting the ‘weed’ species averaged twice that of the DEFRA recommended plants. The study also found that several nationally rare or scarce insect species particularly visited the ‘weeds’.

It appears that many common British wildflowers that are valuable to flower-visiting and herbivorous insects are often overlooked or actively disliked and removed. Yet, results clearly show that weeds have an underappreciated value in supporting our natural biodiversity.

Wild plants growing in public spaces are often deemed harmful and removed by councils, while plants that are seen as ‘more desirable’ are planted in their place in order to mitigate this biodiversity loss. All of this comes at a cost to the taxpayer. By simply letting more wild plants grow in designated spaces, councils could save money and better support pollinators.

Thankfully, there is a growing awareness and appreciation amongst the British public for this group of often maligned and underappreciated wildflowers.