How to Grow Stock: A Cottage Garden Staple

Matthiola incana

Stock, Matthiola incana, is a member of the Brassicaceae family of plants that includes cabbages. Originating in Europe, it is easily cultivated in all temperate zones, and is especially prized by cottage gardeners for its terminal clusters of fragrant, showy blossoms.

It is also a favorite of florists who appreciate the robust blooms for their vertical interest, sturdy stems, spicy-sweet aroma, and longevity in vase arrangements.

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In this article, we discuss all you need to grow your own stock flowers.

Here’s the lineup:

Let’s get growing!

M. incana is one of approximately 50 Matthiola species.

Also called gillyflower and ten-weeks, as well as hoary, Brompton, or vintage stock, the native species has been widely cultivated, and today’s varieties come in shades of apricot, lavender, pink, purple, red, white, yellow, and bicolor. There are many hybrid series of plants from which to choose.

Spray types are multi-stemmed with loose terminal blooms.

Like a snapdragon, the blossoms appear sequentially, from bottom to top, and sit above lush, somewhat hairy, grayish-green foliage.

The petals are arranged in either a single or double row, and have a spicy-sweet scent. The occurrence of single or double blossoms is random.

By chilling seedlings and examining their “cotyledons,” or seed leaves, professional breeders are often able to identify and thin out the single-petal types and retain the doubles, to bring the most robust blooms to market.

There are other Matthiola species, including M. longipetala. Visually, this plant pales in comparison, with its sparse, narrow petaled blooms. However, it makes up for its shortcomings by emitting a heady scent in the evening.

M. incana is a cool-weather plant that blooms from early spring into summer.

Stock is referred to as a half-hardy annual, short-lived perennial, or biennial.

How can this be?

In cool regions, it grows as an annual that may withstand a frost or two, hence the term “half-hardy.” Plants may thrive right through to fall in these locales.

M. incana is a tender perennial In USDA Hardiness Zones 7 to 10 that may live for a few years, coming back with woodier stems each spring. Here, it blooms until the summer heat becomes oppressive.

Propagation

Start plants with seeds, divisions, or nursery seedlings.

From Seed 

In Zones 7 to 10, pre-seed the garden or outdoor containers in the fall for early spring blooms.

In cool regions, start seeds indoors eight to 10 weeks before the last average spring frost date.

It is best to use individual seed starter cells for minimal disruption when transplanting to the garden.

Here’s how to sow them indoors:

1. Moisten the potting medium and press two seeds gently into each cell.
2. Barely cover the seeds with an eighth of an inch of soil, as they need light to germinate.
3. Maintain even moisture without oversaturation, by letting the cells almost dry out before watering again.
4. Place the cells in a sunny room with a temperature between 65 and 75°F.
5. The seeds should sprout within two weeks.

After the danger of frost has passed, gradually acclimate the seedlings to the outdoors for a few hours a day, and then transplant them to the garden or containers.

Place the seed starter cells level with the garden soil, to maintain the same planting depth.

When starting from seeds, expect it to take 10 to 12 weeks for them to reach maturity.

There are varieties of M. incana that have been bred to have a shorter growing season ranging from seven to 10 weeks – hence the nickname, “ten weeks.”

Sow these directly outdoors in spring after the frost danger has passed. You’ll find some of the earliest blooming plants in the Cheerful and Cinderella series.

Here’s how to plant them outdoors:

1. Work the soil to a depth of eight to 10 inches, until the large clods are broken up, and a smooth consistency is achieved.
2. Sprinkle a few seeds every nine to 18 inches, depending upon the mature dimensions of your plants. Barely cover them with 1/8 inch of fine soil.
3. Maintain even moisture during germination, but do not oversaturate.
4. When the seedlings have two sets of true leaves, thin them to one every nine to 18 inches.

When the first buds appear, some people like to do what professional growers do, and pinch off the top inch or so of the budded growing tip for a more uniform, compact top.

By Division

If you already grow perennials that come up yearly, divide existing plants to make new ones.

From Seedlings/Transplanting

In both cool and warm regions, you can purchase nursery seedlings to transplant to the garden or containers as soon as they are available in early spring.

Plant at the same depth the seedlings are in their nursery pots. And if you’re container gardening, remember to accommodate the mature dimensions.

How to Grow

Stock flowers thrive in cool weather and rich, well-draining soil. Let’s explore how to meet their needs.

Light

Stock needs full sun to bloom its best. Aim for at least six hours of direct sunlight daily. In areas with hot summers, a bit of afternoon shade can prevent the blooms from fading too quickly.

If you’re growing stock indoors or in a greenhouse, be sure to provide supplemental lighting to mimic long spring days.

Soil

These cool-season annuals demand rich, well-draining soil with a nearly neutral to slightly alkaline pH of 6.8 to 7.5

To determine the composition of the earth in your garden, conduct a soil test through your local agricultural extension.

Temperature and Humidity

For plants to set buds, nighttime temperatures must not exceed 60°F, and they begin to decline once daytime temperatures climb to 80°F.

Water

Provide about an inch of water per week in the absence of rain. Take care to water the soil, and not the leaves, to inhibit fungal growth.

Fertilizer

Fertilize at planting time with a balanced, all-purpose fertilizer or a formula aimed at promoting blooms, such as 5-10-10. Then feed monthly throughout the growing season.

Over-fertilizing with high-nitrogen products can lead to lush foliage at the expense of flowers, so resist the urge to overdo it.

Container Growing

Stock is an excellent choice for containers. Choose pots that can accommodate their mature dimensions, plus an inch to fit in a hose nozzle or watering can spout.

Fill containers with a mix of compost, potting soil, and perlite or coarse sand for drainage.

Water as needed to keep the soil evenly moist and feed monthly with a bloom-focused liquid fertilizer.

Rotate the pot every few days to ensure even sun exposure and prevent leaning stems.

Maintenance

Weed the garden regularly to reduce competition for water, deter pests, and promote air circulation that inhibits fungal growth.

Add a two-inch layer of mulch for weed control, soil moisture retention, and ground cooling.

Where to Buy

There are many cultivated varieties of M. incana from which to choose, ranging in height from 12 to 36 inches tall.

As you shop, you will find seeds and plants that have been bred for exceptional disease resistance, shortened days to maturity, and unusual colors and color combinations.

Imported seed packets often, but not always, include the phrase “phytosanitary certification” to guarantee that they are free of pests and diseases and meet the standards of the receiving country.

Here’s an attractive mix of seeds that you may like. Harmony Mix features blooms in shades of deep violet, rose, purple, pink, and white. Plants mature in 70 to 84 days.

Harmony Mix

Mature heights are eight to 12 inches tall.

Find Harmony Mix stock seeds from Burpee in packages of 100 seeds.

Column Blend features double-petalled flowers in a variety of colors, ranging in height from 24 to 30 inches.

Column Blend

You can find seeds available from Botanical Interests.

Pests and Disease

Quality plants and seeds that grow in conditions that suit them are the least likely to suffer the ravages of pests and disease.

However, sometimes trouble starts with extreme weather conditions, or an infestation or infection in a nearby plant.

Some pests to watch out for when cultivating stock are:

Aphids and cabbage white caterpillars suck the sap from plant tissue, and flea beetles chew it. Try handpicking, spraying with the hose, or treating plants with organic insecticidal neem oil to be rid of them.

Possible diseases that may affect plants include:

• Bacterial Blight
• Damping Off
• Fusarium Wilt
• Gray Mold
• Leaf Spot
• Root Rot
• Verticillium Wilt
• Wire Stem

Best Uses

From neutral to bold shades, the abundant, fragrant blooms of M. incana bring an aura of charm and romance to early-season settings.

With heights ranging from 12 to 36 inches, there are options for front, middle, and rear placements in beds, borders, and container gardening arrangements.

Pair plants with cottage garden favorites like dianthus, heliotrope, iris, larkspur, pansy, petunia, and snapdragon that share similar cultural requirements.

Place them in a pot with calla lily and swan river daisy to highlight each specimen’s unique form.

Mix colors and plant en masse for a sweeping vista to rival the watercolors of the Impressionist masters.

You’re going to love having a ready supply of lush-blossomed cutting flowers when you introduce stock to your outdoor living space!

Did you know that you can keep vase arrangements looking and smelling fresh longer with two easy tips?

1. Remove leaves from the bottom portion of stems that will be under water.

2. Refresh vases daily by snipping the bottoms of all stems and changing the water.

This is especially important for M. incana, as it gets a cabbagey smell if the foliage begins to decompose in vase water. With good care, flowers should stay firm and fresh for at least a week.

Vibrant and Versatile

To recap, stock, or M. incana, does best in cool weather with full sun and moist, well-draining soil of average to moderately fertile quality.

Depending upon where you live, it may behave as a half-hardy annual, tender and short-lived perennial, or biennial.

Its sturdy, upright racemes add vertical interest to early-season gardens with a delightful palette of color-saturated blooms.

In addition to the varied hues, there are different sizes available that are well-suited to multiple garden placements.

It’s time to get out the garden planner. Be sure to add stock for armloads of blooms and the best vase arrangements you’ve ever made!

Does stock grow well where you live? Do you grow it as an annual or perennial? Tell us about your plants in the comments section below.

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