Matthiola incana, known as hoary stock is also known in the USA by the common name tenweeks stock. It is a common garden flower, available in a variety of colours, many of which are heavily scented and also used in floristry.
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 for by the showy spring floral display.
In hard winters there may be some mortality and a well-drained sheltered site suits them best. Growing stock is not a complicated project, but it does require a period of cold.
The duration of cold needed as a part of stock plant care is two weeks for early blooming types and 3 weeks or more for late varieties. Temperatures should remain at 50 to 55 F. (10-13 C.) during this timeframe.
Colder temperatures may damage the roots. If you neglect this aspect of caring for stock plants, blooms will be sparse or possibly nonexistent.
You may wish to purchase seedlings that have already had cold treatment if you live in an area without cooler winters. Cold treatment can be accomplished by growing stock in tunnels of a greenhouse at the right time of year.
Or the frugal gardener can plant seeds in winter and hope your cold spell lasts long enough. In this type of climate, stock flower info says the plant begins to bloom in late spring.
The closely packed flower spikes of this tall, clove scented mix emerge in a blend of at least 6 lovely pastel shades. This customer favorite mingles beautifully in cottage garden borders, or planted in large drifts and containers. Height: 60cm (24″). Spread: 40cm (16″).
Stock plants are generally low-branching that can only reach 12 to 30 inches in height. Dwarf varieties usually grow 8 to 12 inches high.
Stocks are great for use as border edging, garden bedding, or in flowerbeds, windowsill planters, and containers.
They also make good cut flowers. The most popular cultivars are M. longipetala and M. Incana. Matthiola Bicornis is known for its strong fragrance at night.