How to Grow and Care for Stock Flowers

Stock flowers, also known as stock, are pretty cottage garden plants that come in a range of colors and have a delicate fragrance that many associate with heirloom flowers. It has been said that Thomas Jefferson had them imported to plant at his gardens at Monticello in 1771, thereby introducing them to cultivation in the United States.

The original native species has been widely cultivated and hybridized, such that it now comes in a wide array of colors, from pleasing pastel pink and apricot to vibrant shades of crimson and purple. Some varieties grow up to 3 feet tall, though most are between 12 and 24 inches. The flowers may be tightly clustered or spaced somewhat loosely on the spiky stems, sometimes appearing as double blooms, and the leaves are narrow and oval. Stock flowers grow best in full sun to part shade, in rich, evenly-moist soil, but prefer cooler weather—blooming will pause once temperatures reach above 65 degrees Fahrenheit.

Stock Flower Care

Here are the main care requirements for growing stock flowers:

• Ensure stock flowers get 2-3 hours of sunlight a day, preferably indirect light and morning sun for the most blooms.
• Plant in rich, well-drained, neutral soil.
• Keep soil evenly moist—top with a layer of mulch to help retain water and keep roots cool.
• Avoid extreme heat and humidity, stock flowers prefer cooler temperatures.
  

Light

Stock flowers enjoy full sun but will bloom just fine in partial shade conditions, as long as they get at least 2-3 hours of sun per day; indirect sunlight will also keep them blooming. Too much hot bright sunlight will overwhelm them, so morning sun is better than afternoon sun.

Soil

These flowers like a rich, well-drained soil that has a pH close to neutral. If your soil tends to be acidic, you can add a bit of lime or wood ash to sweeten it, or use a commercial potting soil if growing in containers.

Water

Water regularly in the heat of summer, but be careful not to overwater, as this can yellow the leaves.

Temperature and Humidity

Matthiola incana is somewhat sensitive to temperature, which is what makes it a "half-hardy annual" in some locations, meaning it will keep blooming through one or two frost events. It likes cool weather, but cold winters may prevent it from returning as a perennial. It doesn't like extreme humidity and so consistently moist, tropical conditions are not ideal.

Fertilizer

Stock doesn't tend to need fertilizer, but it's somewhat particular about soil. A layer of natural mulch will help keep weed growth down and keep the soil evenly moist and cool for optimal growing conditions.

Types of Stock Flower

Stock's botanical name is Matthiola incana, and it is a member of the brassica family. The blue-green leaves do somewhat resemble tiny cabbage leaves, and when the flowers drop off the remaining foliage looks somewhat like brassicas gone to seed. There are at least fifty different Matthiola species; Matthiola bicornis, or evening scented stock, is a species with somewhat larger flowers. There are many different varieties of Matthiola incana available, owing to many years of hybridizing efforts to develop a wide range of colors. Examples of stock varieties include:

• 'Cinderella': a compact variety that grows no more than 12 in. tall, and has full double flowers in many beautiful pastel shades and some brights.
• 'Legacy': grows up to 2 ft. tall and bears large double flowers in a variety of bright vivid shades including crimson and purple.
• 'Starlight Scentsation': grows to 18 in. in height and bears dramatic clusters of single flowers in a range of colors.
• 'Iron': a series of large double-flowered stock on sturdy stems in a range of colors, and the variety used by many florists for arrangements.
• 'Antique Pink': features a two-tone pink flower that's usually double; the colorful petals surround pale green centers, a very romantic look.

Pruning

Deadheading stock flowers after the petals wilt keeps the plants looking neat and may help generate new growth and possibly more blooms (this varies from one variety to another).

Growing Stock Flowers From Seed

Stock can be grown easily from seed, but should be sown early as it tends to wilt a bit in late summer heat. Here's how:

1. Sow seeds in rich neutral soil, barely covering with 1/8 of soil.
2. Maintain good moisture by spraying but don't oversaturate soil.
3. Seedlings should appear within 10-14 days.

Common Pests and Diseases

Stock may be bothered by aphids, flea beetles, and cabbage white caterpillars. If you see pests on the leaves, gently remove them and cut off any damaged plant parts. They may also be vulnerable to the following diseases: fusarium wilt, gray mold, leaf spot, root rot, and verticillium wilt. Avoiding overwatering will help prevent most of these.

How to Get Stock Flower to Bloom

Bloom Months

Stock flowers bloom in the spring and summer months of May through July. In cooler weather, they can also bloom in the fall.

What Do Stock Flowers Look and Smell Like?

Stock flowers can have either single or double blooms that grow in clusters on spiky stems. Stock has a subtle, clove-like scent and attracts pollinators like bees and butterflies. Stock flowers' blooms come in a wide range of colors, including pink, apricot, yellow, purple, blue, red, and white.

How to Encourage More Blooms

Deadhead spent blooms to promote new growth and flowering. As a cool-weather annual, hot summer temperatures will stunt new flower growth.

Common Problems

Stock flowers are easy to grow in a home garden, but certain conditions—namely poor air circulation, overwatering, poor drainage, or wet, humid conditions—can trigger viral and fungal diseases. Keep an eye out for these issues. 

Gray Mold

Gray mold can affect plants where there’s poor air circulation and humid, cool weather. Remove diseased plants, space out plantings, and water using drip irrigation.

Yellowing Leaves

Poor air circulation and wet conditions can cause leaves to turn yellow and grow fuzzy spores from downy mildew. Try drip irrigation and space out plantings. If leaves turn yellow and fall off, verticillium wilt may have spread through contaminated tools or soil. Remove diseased plants and rotate plantings.

Brown Spots

Hot, humid, and wet conditions can promote the growth of leaf spot. Space out plants, use drip irrigation, and remove diseased plants.

Wilting Plants

High humidity, poor air circulation, overwatering, or poorly drained soil can cause root rot. Remove affected plants, space out plantings, and improve soil drainage.