Saint-John’s-wort, also called hypericum, is a group of herbs and shrubs with large yellow flowers. There are hundreds of species (kinds). Most St.-John’s-worts grow in the temperate (mild) and warmer regions of the Northern Hemisphere. The plants are usually low shrubs. Some St.-John’s-worts are evergreen. The flowers of these plants bloom in clusters in summer. Pink or purplish flowers are rare. St.-John’s-worts grow well in loam or moist, sandy soil. Some grow well in shady locations. The larger St.-John’s-worts form rounded bushes when grown alone. The smaller ones make good low borders or ground cover in gardens. Many people use extracts of common St.-John’s-wort as a remedy for mild forms of depression. But scientists are not certain whether the herb can effectively treat mental illness.