Stock, also known as Matthiola, is a hardy cool-season annual native to the Mediterranean and a favorite in old-fashioned cottage gardens. The tightly clustered flowers come in shades of white, pink, red, cream, peach, yellow, lilac or purple, and may be single or double. Because of their sweet and spicy fragrance, spikes of stock blossoms are often sold as a cut flower. The most commonly planted forms are common stock (Matthiola incana), which ranges from 8 to 30 inches tall, and evening-scented stock (Matthiola longipetala bicornus), which is 12 to 14 inches tall.
Starting Stock From Seed
Start seeds indoors in a sunny spot six to eight weeks before the last frost. Plant seeds in a well-draining potting mix, as stock is susceptible to rot, or damping-off. Water from below just enough to keep the potting mix moist. The best temperature for germination is 55 to 65 degrees.
Press the seeds lightly on the planting mix, but don't bury them, as they need light to germinate.
Read the seed packet to learn how to distinguish between seedlings of single and double flowers for your variety (for example, double “Ten Week” stock seedlings are a darker green than the singles). Pinch out the singles, as doubles offer more interest and more perfume, according to Larry Hodgson in “Annuals for Every Purpose.”
Caring For Stock In The Garden
Locate a spot in full sun to partial shade. Using a trowel or spade, prepare the garden soil by amending it with organic matter such as shredded leaves or a light compost. Stock prefers a light, fertile soil with good drainage. Space seedlings or nursery plants 10 to 15 inches apart, and plant at the same level they were growing in their pots. Water well after planting. Keep the soil moist throughout the growing season, but do not overwater, as stock is prone to root rot.
Plant seedlings or nursery-grown plants outside in the early spring in cold weather climates. Stock blooms best in cool weather, so plant early to get maximum enjoyment from the flowers before warm weather arrives.
Plant in the early fall in climates with a milder winter, for bloom in winter or early spring. Stock will withstand moderate frost, but will not set bloom if temperatures too cold at night.
Fertilize monthly with an all-purpose fertilizer intended for annual flowers. Using pruning shears, deadhead stock when flower spikes are done blooming. This needs to be done only to keep the plants looking neat, as the double-flowered stocks do not produce seed.
Caring For Stock As A Cut Flower
Purchase stock when half to two-thirds of the flowers on the stalk are open. Look for straight, sturdy stems, and avoid stems on which the lower flowers are decaying.
Remove any foliage that will be below the water line of the vase or container. For longest flower life, cut the stem under water and use a floral preservative.
Change the water of your stock bouquet daily because stock is susceptible to mildew, FloralDesignInstitute.com recommends.