Stock flowers (Matthiola incana) earn their place in the spring garden with upright spikes of tightly packed blooms and a fragrance that carries across a border. The plants grow 12 to 24 inches tall, with some varieties reaching 3 feet, and flower in shades of pale pink, apricot, crimson, purple, and white. They bloom quickly from seed and tolerate cool weather, which makes them one of the most reliable fast-growing flowers for a vibrant cutting garden. A single sowing starts producing stems ten to twelve weeks after the seed goes in the ground.
Stock is a cool-season plant, treated as a spring and early-summer annual in most regions and grown for a fall show in mild coastal areas. The original Mediterranean species was among the first European ornamentals brought to North American gardens; Thomas Jefferson imported stock for his gardens at Monticello in 1771. Heavy hybridization since then has produced the wide color range, the double blooms, and the tight clusters gardeners know today.
Stock Flowers at a Glance
The table below summarizes the essentials for growing stock, from planting through bloom. The two numbers that matter most are the 10 to 12 weeks from seed to flower and the cool temperatures that keep the plants producing.
| Trait | Detail |
|---|---|
| Common name | Stock, ten-week stock, stock gillyflower |
| Botanical name | Matthiola incana |
| Family | Brassicaceae |
| Plant type | Cool-season annual, sometimes biennial |
| Mature size | 12-24 in. tall, up to 3 ft. for some varieties |
| Sun exposure | Full sun to part shade |
| Soil type | Rich, evenly moist, well-drained |
| Soil pH | 6.0 to 7.5 |
| Bloom time | Spring to early summer |
| Flower color | Pink, apricot, crimson, purple, white |
| Native area | Mediterranean Europe |
Stock belongs to the Brassicaceae family, the same group as cabbage and mustard, and the common name comes from an Old English word for stem or stalk. The flowers may be tightly clustered or spaced loosely along the spike, and the narrow, oval leaves stay low at the base of the stems.
A Flower With Colonial Roots
Heirloom strains carry the strongest fragrance and the classic narrow leaves. Hybrid ten-week stocks bloom faster and hold petals longer in the vase, which is why commercial cut flower growers plant them almost exclusively. Both types grow in the same conditions.
From Heirloom to Hybrid
The double-flowered forms favored for bouquets produce few seeds, so seed companies maintain them by crossing selected parents each year. Save seed from single flowers if you want to collect your own.
In the border, the plant’s upright spikes contrast with broad-leafed companions. When stock finishes in early summer heat, bold tropical plants such as canna lily take over the same bed, so the space keeps producing color through the hottest months.
Light and Temperature Needs
Stock flowers best in full sun, defined as at least six hours of direct light a day, and tolerates part shade where afternoons run hot. Cool temperatures matter more than light. The plants prefer daytime highs in the 60s and low 70s Fahrenheit and slow down once nights stay consistently warm, which is why they perform so well in spring and early summer.
The plants fit naturally into the small beds around a house, where eaves and fence lines create pockets of cooler shade. A growing family that plants a few rows each spring finds stock forgiving of light frost and uneven watering, so the garden can expand a little every year without a large budget.
Managing Heat in Warmer Zones
South of zone 7, grow stock as a spring-only crop. Sow as early as the soil can be worked, mulch the roots to keep them cool, and expect the bloom period to shorten once temperatures climb past 80 degrees Fahrenheit.
Cool Nights, Long Stems
Cut flower growers prize the long, straight stems that stock produces in cool conditions. Night temperatures near 55 degrees Fahrenheit encourage the plants to stretch, and the same response makes stock a natural crop for spring hoop houses and cold frames.
Soil, Water, and Fertilizer
Stock prefers rich, evenly moist soil with good drainage. Work compost or aged manure into the bed before planting, and keep the pH between 6.0 and 7.5. Water deeply once or twice a week so the root zone stays moist but never soggy, and feed with a balanced fertilizer at planting and again every month through the growing season.
Improving Heavy Soil
Clay soils hold water too long and can rot the crowns. Amend with compost and coarse sand, or grow stock in raised beds and containers where drainage is easier to control. A 3-inch layer of mulch slows evaporation and keeps the root zone cool.
Feeding Schedule
A 10-10-10 fertilizer worked into the soil at planting supplies the phosphorus stock needs for heavy blooming. Switch to a liquid feed diluted to half strength every two weeks once buds form, and stop feeding when the weather turns hot.
The color range runs from pale pastels to saturated jewel tones. Deep maroon varieties look almost black in evening light, and gardeners who enjoy that drama often pair stock with black flowers for a bold and dramatic garden design that keeps the border interesting after the stock fades.
How to Plant Stock From Seed
Stock germinates quickly and flowers in ten to twelve weeks, so one sowing covers most of the spring season. Seed can go directly into the garden or start indoors under lights, and both methods reward a little care at planting time.
Direct Sowing vs. Indoor Starts
Direct sowing suits mild climates and busy schedules:
- Wait until about two weeks before the last frost date; stock tolerates light frost.
- Rake the bed smooth and scatter seed thinly over the surface.
- Cover with an eighth of an inch of fine soil or vermiculite, because seed needs light to germinate.
- Keep the surface moist with a fine spray until seedlings appear in 7 to 14 days.
- Thin seedlings to 8 to 12 inches apart so air moves freely around each plant.
For indoor starts, sow in cell trays six to eight weeks before the last frost, keep the mix at 65 to 70 degrees Fahrenheit, and provide strong light the moment seedlings emerge.
Hardening Off Seedlings
Move seedlings outside for a few hours each day over a week, starting in shade and working up to full sun. Gradual exposure prevents transplant shock, which stalls growth and delays blooming by a week or more.
Whatever method you choose, plant extra rows if you pick blooms for the house. Stock is one of the most fragrant cut flowers for stunning homemade bouquets, and cutting each stem encourages side shoots that keep the plant blooming for weeks.
Pruning, Deadheading, and Support
Stock needs little pruning, but two simple practices keep plants compact and blooming. Pinch the growing tips when seedlings reach 4 to 6 inches tall to force branching, and deadhead spent spikes regularly so the plant pushes out new buds instead of setting seed.
Pinching for Bushier Plants
Pinch or snip the top inch of the main stem once, early in the season. The plant responds by sending up multiple flowering stems from the leaf axils, which adds fullness to both borders and bouquets.
Staking Tall Varieties
Three-foot varieties flop in exposed sites. Set supports early, before the stems fill out, and tie loosely with soft twine so the ties do not cut into the stalks. Single stakes work for most plants, while tall doubles may need a ring support.
The care routine tracks closely with snapdragon care essentials: pinch young plants, deadhead faithfully, and cut stems for the vase to extend the show. Both plants belong in the cool-season cutting garden, and they share the same watering and feeding schedule.
Common Pests, Diseases, and Problems
Aphids cluster on new growth and flower buds, and flea beetles riddle the leaves with small holes. Knock aphids off with a strong spray of water or treat with insecticidal soap, and protect young plants from flea beetles with floating row cover until they are established.
Aphids and Flea Beetles
Check the undersides of leaves weekly, because both pests multiply fast in cool weather. A few beetles rarely matter, but heavy feeding on seedlings can set the plants back for weeks. Avoid these common mistakes:
- Sowing into cold, wet soil that rots the seed before it germinates.
- Letting seedlings dry out during the germination window.
- Skipping the early pinch, which leaves plants leggy.
- Leaving spent flowers on the plant, which shortens the bloom period.
Damping Off and Clubroot
Damping off kills seedlings at soil level when conditions stay wet and crowded. Use fresh seed-starting mix, water from below, and keep air moving. Clubroot, a soilborne disease, distorts the roots of plants in the cabbage family; rotate stock away from other brassicas and avoid replanting in soil where clubroot has appeared.
The most common problem is simple heat. When stock stops blooming and the lower leaves yellow in summer, that planting is finished. Pull the plants and replace them with heat-tolerant celosia plants, which grow quickly from seed and carry the same bed through the hot months with plume and cockscomb flowers.
Collect seed from single-flowered plants if you want to save your own; doubles produce little viable seed. Stored in a cool, dry jar, stock seed stays usable for two to three years.