Heirloom

Katz Purple

Matthiola incana

Photo: paciana · Wikimedia Commons · (CC BY 3.0)

Long stems with 1 1/2-2", dark purple blooms. Early blooming one-cut series. Performed well in our spring, early summer, and fall trials. Good uniformity in bloom time and stem length. 55-60% double-flowering without selection; some selection possible. NOTE: This variety produces one flowering stem per plant. Pinching is not advisable as it will terminate flowering. Edible Flowers: The peppery, clove-like flavor of the flowers lends itself well to use as a garnish on salads, desserts, and drinks.

Harvest

90-100d

Days to harvest

📅

Sun

Full sun to partial shade

☀️

Zones

6–10

USDA hardiness

🗺️

Height

1-3 feet

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Start Indoors

Transplant

Direct Sow

Start Indoors

Transplant

Direct Sow

Showing dates for Katz Purple in USDA Zone 7

All Zone 7 flower →

Zone Map

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Katz Purple · Zones 6–10

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing12-18 inches

SeasonWarm season annual

FlavorPeppery, clove-like flavor ideal for edible garnishes on salads, desserts, and drinks.

ColorDark purple

Size1 1/2-2"

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 3	April – May	June – July	June – August	—
Zone 4	March – April	June – June	June – July	—
Zone 5	March – April	May – June	May – July	—
Zone 6	March – April	May – June	May – July	—
Zone 7	February – March	April – May	April – June	—
Zone 8	February – March	April – May	April – June	—
Zone 9	January – February	March – April	March – May	—
Zone 10	January – January	February – March	February – April	—
Zone 1	May – June	July – August	July – September	—
Zone 2	April – May	June – July	June – August	—
Zone 11	January – January	January – February	January – March	—
Zone 12	January – January	January – February	January – March	—
Zone 13	January – January	January – February	January – March	—

Succession Planting

Stock is worth succession planting if you're cutting for market or a CSA share, since each plant gives you one main flush of bloom. Sow indoors every 3 weeks from early February through mid-March in zone 7, then start a fall round indoors in late July for September transplant. Skip a summer sowing — Katz Purple won't perform with daytime highs above 80°F, and the stunted spikes you'd get aren't worth the tray space.

Complete Growing Guide

Light: Full sun (6 or more hours of direct sunlight a day), Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: Clay, High Organic Matter, Loam (Silt), Sand. Soil pH: Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 1 ft. 0 in. - 3 ft. 0 in.. Spread: 0 ft. 9 in. - 1 ft. 6 in.. Spacing: Less than 12 inches, 12 inches-3 feet. Growth rate: Rapid. Maintenance: Low. Propagation: Seed. Regions: Coastal, Mountains.

Harvesting

Katz Purple reaches harvest at 90 - 100 days from sowing per Johnny's Selected Seeds. Expect 1 1/2-2" at peak. As an annual, harvest continues until frost ends the season.

Seeds will ripen in August and September.

Harvest time: Fall

Storage & Preservation

Fresh Katz Purple flowers are best stored in the refrigerator at 35-40°F with high humidity (90-95%) to maintain petal firmness and color vibrancy. Store in a shallow vase with water or wrapped in damp paper towels in a sealed plastic bag; they typically last 5-7 days when refrigerated. For preservation: (1) Air-dry petals on parchment paper in a cool, dark space for 2-3 weeks to use as edible garnishes year-round; (2) Freeze petals in ice cube trays with water for cocktails and desserts, lasting 2-3 months; (3) Candy petals using egg white and superfine sugar for decorative confections with 4-6 month shelf life in airtight containers.

History & Origin

Katz Purple is open-pollinated, meaning seed saved from healthy plants will produce true-to-type offspring. Listed in the Johnny's Selected Seeds catalog.

Origin: The Coast of Europe from Spain to Greece.

Advantages

+Dark purple blooms create striking visual impact in floral arrangements
+Excellent uniformity in bloom time and stem length across plantings
+Early flowering series reaches maturity in just 90-100 days
+Edible flowers add unique peppery, clove-like flavor to culinary presentations
+Performed consistently well across spring, summer, and fall growing seasons

Considerations

-Single flowering stem per plant limits yield compared to pinchable varieties
-Cannot be pinched to encourage branching without completely terminating flower production
-Only 55-60% naturally produce double flowers without additional selection work

Companion Plants

Sweet alyssum (Lobularia maritima) is the most useful companion here — it draws parasitic wasps and hoverflies that knock back aphids, which do occasionally find stock. Marigolds (Tagetes spp.) nearby add a similar effect and help confuse thrips. Cosmos and zinnias are good neighbors because they don't compete hard for root space at 12-18 inch spacing and keep pollinators cycling through the bed. Keep stock well away from fennel (Foeniculum vulgare), whose root exudates suppress many annuals, and away from black walnut (Juglans nigra) — stocks are notably sensitive to juglone and will show it.

Plant Together

Marigolds

Repel nematodes and aphids while attracting beneficial insects

Nasturtiums

Act as trap crops for aphids and cucumber beetles, attract pollinators

Lavender

Deters moths, fleas, and mosquitoes with aromatic oils

Sweet Alyssum

Attracts beneficial insects like hoverflies and parasitic wasps

Cosmos

Attracts beneficial insects and provides habitat for predatory insects

Zinnia

Attracts butterflies, bees, and beneficial predatory insects

Catmint

Repels ants, aphids, and rodents while attracting pollinators

Sunflowers

Provide beneficial shade and attract pest-eating birds

Keep Apart

Black Walnut

Produces juglone toxin that inhibits growth of most flowering plants

Eucalyptus

Releases allelopathic compounds that suppress nearby plant growth

Fennel

Inhibits growth of most garden plants through allelopathy

Troubleshooting Katz Purple

What you'll see, why it happens, and what to do about it.

Seedlings collapse at the soil line, stems pinched and dark, within the first 2-3 weeks after germination

Likely Causes

Damping off (Pythium or Rhizoctonia spp.) — triggered by overwatering and poor air circulation around seedlings
Sowing too deep in heavy, slow-draining seed-starting mix

What to Do

1.Water only when the top of the mix is dry to the touch; Matthiola seedlings do not want wet feet
2.Run a small fan on low near your seed trays for 1-2 hours a day to keep air moving
3.If damping off has hit one tray, don't try to save it — start fresh with sterile mix and clean containers

Leaves develop pale yellow patches on top with a gray-purple fuzzy coating on the underside, usually after a stretch of cool, humid weather

Likely Causes

Downy mildew (Peronospora parasitica) — a Brassica-family pathogen that hits stocks hard when nights stay below 60°F and humidity is high

What to Do

1.Space plants at least 12 inches apart — crowded stock beds stay wet longer and move far less air
2.Strip affected leaves and dispose of them in the trash, not the compost pile
3.Switch to drip irrigation or early-morning hand watering at the base; evening overhead watering is the fastest way to make this worse

Plants flower early but produce short, weak spikes with few florets, often under 12 inches tall

Likely Causes

Heat stress — stock bolts and stunts when daytime temps push past 75-80°F before the plant has sized up
Transplanting too late in spring, leaving insufficient cool-season growing time before summer arrives

What to Do

1.Start indoors 8-10 weeks before your last frost date so plants are well established before warm weather lands
2.Get direct-sown seed in the ground by mid-April in zone 7 — waiting until May usually costs you spike quality
3.In hot climates, treat stock as a fall crop: transplant in September for bloom October through December

Frequently Asked Questions

How long do Katz Purple flowers last once cut?▼

Katz Purple flowers typically last 5-7 days when properly stored in the refrigerator. Keep them in a vase with fresh water or wrapped in damp paper towels in a sealed plastic bag at 35-40°F for maximum vase life. Remove any foliage below the water line to prevent bacterial growth and extend freshness.

Are Katz Purple flowers good for beginners?▼

Yes, Katz Purple is an excellent choice for beginning growers. It's rated as an easy-difficulty variety and requires only basic care: full sun to partial shade (4-6+ hours), regular watering, and no pinching or special handling. The plants are reliable and perform well across multiple seasons.

Can you grow Katz Purple in containers?▼

Yes, Katz Purple can be successfully grown in containers. Use a well-draining potting mix and ensure pots have drainage holes. Container size should be at least 8-12 inches deep to accommodate the root system. Regular watering is essential since containers dry out faster than garden soil.

What does Katz Purple taste like as an edible flower?▼

Katz Purple flowers have a distinctive peppery, clove-like flavor profile. The blooms work well as edible garnishes on salads, desserts, and drinks, adding both visual appeal and a subtle spicy-aromatic note. The flavor complements sweet and savory dishes alike.

When should I plant Katz Purple seeds?▼

Sow Katz Purple seeds indoors 6-8 weeks before your last spring frost date, or direct sow outdoors after all frost danger has passed. The variety takes 90-100 days to reach flowering from planting. For continuous summer and fall blooms, stagger plantings 2-3 weeks apart.

Does Katz Purple produce multiple stems per plant?▼

No, Katz Purple is a one-cut variety, producing only a single flowering stem per plant. Do not pinch or deadhead the main stem, as pinching will terminate flowering and result in lost blooms. This makes it ideal for cut flower production with predictable yield.