How to Plant and Grow Stock

Stock flowers offer a wonderfully spicy, distinctive scent that is reminiscent of cloves. They are especially wonderful in window boxes and planters at nose level, where their sometimes-subtle effect can best be appreciated. Stock plants are slightly spirelike and their blooms come in a wide range of colors. They also make great cut flowers and are favored by florists for their long-lasting flowers and their intoxicating perfume.

Plant stock in spring several weeks before your region's last frost date as these hardy annuals thrive in cool temperatures and stop blooming once hot weather arrives.

Where to Plant Stock

Stock plants grow best in full sun or part shade and moist, well-drained soil. They are excellent for cottage gardens or planted near seating areas where their perfume can be appreciated. While they are most often grown as annuals, stock plants are hardy in zones 7 through 10 as biennials or short-lived perennials.

You can also grow stock in containers and flower boxes, just be sure to choose a container that is at least 1 or 2 inches larger in diameter than the plant’s projected width at maturity.

How and When to Plant Stock

In cooler climates, stock seeds should be started indoors about 6 to 8 weeks before the last frost. Seedlings can be transplanted outdoors (after a brief hardening off) in early spring. If you are planting nursery starts, dig a hole roughly the same size as the nursery pot and place your plants about 6 to 12 inches apart.

If you are planting seeds directly in the ground, you can do so after the last spring frost. Sow the seeds on the surface of the soil and moisten them daily until the seeds begin to germinate. Once the seeds sprout, thin the seedlings until they are about 6 to 12 inches apart.

Stock Care Tips

Stock flowers need little care once they are established. Mature plants are relatively drought-tolerant and only require some deadheading to stimulate regrowth throughout the season.

Light

Stock flowers prefer full sun but can also bloom in partial shade as long as they get a few hours of sun per day. For the healthiest, happiest blooms, plant your stock flowers in a place where they will be bathed in morning sunlight rather than the intense beams of the afternoon sun.

Soil and Water

Stock flowers enjoy rich, moist, well-draining soil with a neutral or slightly alkaline pH (ideally 6.5 to 7.5). Turn the soil about 8 inches deep and mix in some compost if you need to amend your soil before planting (or incorporate some lime if your soil is on the acidic side). You can also top-dress the soil with mulch to keep weeds at bay and help the soil stay evenly moist.

Temperature and Humidity

Stock plants prefer cool, semi-tropical climates and will stop blooming in the summer when temperatures above 65 degrees cause them to wither. They can overwinter in very mild climates and are considered “half-hardy” annuals in some zones where they will withstand one or two frosts.

Fertilizer

Stock plants do not need fertilizer to thrive if they are planted in the proper soil. You can apply a light fertilizer, following manufacturer's instructions, after new growth appears on young plants if you like. Limit applications to once a month and keep an eye on how the plants fare as too much fertilizer can cause root rot.

Pruning

To keep your stock plants looking tidy and producing new growth until the fall, deadhead spent blooms immediately. Just pinch off the dead blossoms between your fingers or—if all the blossoms have waned—cut off the entire flower spike. Just cut the stalk as close to the base as possible to direct the plant’s energy into producing new stalks.

Potting and Repotting

The steps for growing stock plants in containers are largely the same as caring for stock plants that are planted in the ground. The plants will need moist, well-draining soil that is relatively neutral. Pay close attention to the plant tags and choose a container that can accommodate the growth habits of the stock plant you have chosen. To keep the container from being too top-heavy, it’s best to stick with shorter varieties.

Pests and Problems

Stock plants are prone to issues with gray mold, leaf spot, root rot, fusarium wilt, and verticillium wilt, but most of these issues can be prevented by not overwatering your plants.

Stock plants also have occasional issues with aphids, flea beetles, spider mites, and whiteflies. If you see them, do your best to gently remove them or trim the damaged portions of the plant.

How to Propagate Stock

To grow stock plants from seeds, start them indoors about 6 to 8 weeks before the last frost. Press the seeds gently into a tray of rich, well-draining, neutral soil and lightly sprinkle more soil on top (the seeds will need light to germinate). Spritz some water on the surface of the soil and then cover the tray with plastic wrap or glass. Keep the soil moist for about 10 to 14 days, spritzing every day but never oversaturating the soil. Once the seeds have begun to sprout, you can harden off your starts by acclimating them to outdoor temperatures for a few hours each day for a few days and then transplant them into your garden or outdoor container. It may take 10 to 12 weeks for your plants to reach full maturity.

You can also propagate stock plants from cuttings at the end of the season when warmer weather kicks in. Just snip off a shoot (at least 2 inches) and remove any remaining flowers or buds from the shoot, snipping away all but a few leaves. Dip the cut end of the shoot into a rooting hormone and plant it in some good, organic compost. Gently press the soil against the stem to keep it sturdy and upright in the pot. Set cuttings in bright, indirect light and keep the soil moist but not wet. New roots should form a few weeks after planting a cutting.

Types of Stock

'Cinderella' stock

Matthiola Cinderella Series stock plants bear double flowers in a range of shades. The compact plants grow 10 inches tall.

'Legacy' stock

Matthiola Legacy Series stock plants bear double flowers in a range of bright shades. They grow 2 feet tall.

'Starlight Scentsation' stock

Matthiola 'Starlight Scentsation' shows off strongly fragrant single blooms in a range of colors. It grows 18 inches tall.

Companion Plants for Stock

Stock plants will thrive among other common cottage garden plants that prefer similar growing conditions like moist, well-draining soil and cool, but sunny weather.

Heliotrope

Heliotrope's abundant flowers add splashes of color while perfuming the air with a heady scent that has been likened to vanilla, baby powder, grapes, or cherry pie. It fares best in well-drained soil with full sun.

Phlox

Phlox is another classic cottage garden plant that can add height, heft, and charm to any border or bed. Phlox paniculata 'David' is a pretty (and disease-resistant) selection that grows 4 feet tall and has fragrant, pure-white flowers. Or, to edge a garden bed, try a low-mounding creeping phlox that features evergreen foliage and bright spring flowers.

Dianthus

Dianthus is a creeping groundcover known for its grass-like foliage and starry pink flowers that give off a spicy, clove-like fragrance much like stock flowers. It prefers full to partial sun and well-draining, neutral to slightly alkaline soil.

Larkspur

With its airy stocks of blue, purple, white, and pink blossoms, larkspur is a pretty addition to any garden bed. If you plant them with stock plants, put your larkspur plants in the sunniest spots because they prefer full sun and can tolerate more direct sunlight.