Spring has given way to mid-summer and nature’s floral display has moved on. One group of plants that come into flower at this time of year are the Hypericum species, St John’s-wort. There are about a dozen UK species living in habitats from woodland to heath and even bogs. They all have five petalled yellow flowers with clusters of orange tipped stamens. They range from the Rose of Sharon shrub with its 7-8cm flowers down to the tiny 1cm stars of Trailing St John’s-wort.

Also known as Goatweed because the leaves have a sour smell if crushed, the name St John’s-wort is said be because the flowers appear around St John’s Day 24th June. Traditionally, the flowers adorn pictures of the saint on his day. The reddish sap that can ooze from cut stems is supposed to mark his terrible murder.

Wort implies a herbal remedy and the plants have been used for centuries to lift moods of sadness. There is now good scientific evidence that it works, St John’s-wort is a summer flower that can raise a smile.

Many Hypericum species have black dots around the edges of the petals and leaves and others have translucent dots on the leaves, these are glands that secrete complex oils rich in several aromatic chemicals. These have a number of proven and potential medicinal properties not just as an antidepressant. St John’s-wort needs to be taken cautiously because, as with conventional medicines, there can be side effects.

The Sid Valley Biodiversity Group’s wild flower survey has recorded eight different species in the area. The three species you are most likely to come across are Tutsan, Perforate and Square-stalked St John’s-wort. The shrubby Tutsan can be found in local hedgerows with large yellow flowers giving way to berries of a deep claret colour. Perforate St John’s-wort is found at the edges of roads and dry meadows such as Alma Field and has the translucent leaf glands that look like pin holes if you hold a leaf up to the light. It’s square-stalked cousin prefers damper places such as the grounds of Knowle and is easy to recognise because of the four wings that give the stalk its square shape.