Matthiola incanaMatthiola incana is one of several species of stock, and is sometimes called hoary stock. It is a common garden flower, available in a variety of colours. Some stocks are grown as annuals (the "Ten-week Stocks"). These varieties are sown in spring (generally from March onwards in colder areas, earlier in regions with mild winters). They give a good summer flower display. Other varieties take longer to develop and are treated as biennials. These are often referred to as "Brompton stocks". In cool temperate regions they are generally sown in summer (June and July) to flower in the following spring. The extra trouble of overwintering the plants is compensated by the showy spring floral display. In hard winters there may be some mortality and a well-drained sheltered site suits them best.