Heirloom

Katz Lavender Blue

Matthiola incana

Photo: Henry G. Gilbert Nursery and Seed Trade Catalog Collection.; Peter Henderson & Co. · Wikimedia Commons · (Public domain)

Long stems with 1 1/2-2", pale 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 Lavender Blue in USDA Zone 7

All Zone 7 flower →

Zone Map

Click a state to update dates

Katz Lavender Blue · Zones 6–10

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

SeasonWarm season annual

FlavorPeppery, clove-like flavor with floral notes.

ColorPale purple

Size1 1/2-2"

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
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	—
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	—

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 Lavender Blue 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

For fresh lavender blooms, store in a cool location away from direct sunlight. Keep stems in water at room temperature (65-70°F) or refrigerate at 35-40°F for extended vase life of 7-10 days. Maintain moderate humidity to prevent wilting. For preservation: (1) Air-dry bundles hung upside down in a cool, dark, well-ventilated area for 2-3 weeks to retain color and fragrance. (2) Freeze flowers in ice cube trays with water for culinary and beverage use. (3) Press flowers between parchment paper under weight for 1-2 weeks for decorative arrangements and crafts.

History & Origin

Katz Lavender Blue 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

+Long stems ideal for cutting and floral arrangements
+Early blooming variety produces flowers in 90-100 days
+Excellent uniformity in bloom time and stem length
+Edible flowers add peppery clove flavor to culinary dishes
+Performed consistently well across spring, summer, and fall trials

Considerations

-Produces only one flowering stem per plant limiting yield
-Single stem nature makes pinching impossible for branching
-55-60% double-flowering rate requires selection for best blooms

Companion Plants

Rosemary, sage, thyme, and catmint make good neighbors for Katz Lavender Blue because they run on similar inputs — full sun, lean to moderate soil, sharp drainage. None of them are heavy feeders, and their root systems stay shallow enough that they won't compete hard with stock's. Alliums (ornamental or culinary) add something more specific: their sulfur compounds are thought to deter aphids, which do find Matthiola attractive, and their upright forms give a useful visual contrast to stock's vertical spikes. Echinacea and Russian sage fit in for practical reasons — both are drought-tolerant and open-structured enough that they don't shade shorter plants out.

Mint is the one to pull before it gets started. It spreads through underground runners fast enough to physically displace stock within a single growing season. Hostas and impatiens are a different problem — both are built for consistent moisture and shade, which is essentially the inverse of what stock wants. Planting them together doesn't split the difference; one plant just declines, and it's stock.

Plant Together

Rosemary

Similar water and soil requirements, both repel deer and rabbits

Sage

Complementary Mediterranean herbs with similar growing conditions

Thyme

Attracts beneficial pollinators and has matching drought tolerance

Catmint

Deters aphids and ants while attracting bees and butterflies

Echinacea

Attracts beneficial insects and provides contrasting flower colors

Sedum

Similar low-water needs and provides late-season pollinator food

Russian Sage

Compatible growth habits and extends blooming season

Alliums

Repel aphids and other pests while requiring similar well-draining soil

Keep Apart

Impatiens

Requires frequent watering which can cause root rot in lavender

Mint

Aggressive spreader that competes for space and prefers moist conditions

Hostas

Needs shade and consistent moisture, opposite of lavender's sun and dry requirements

Troubleshooting Katz Lavender Blue

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

Seedlings collapse at soil level, stems pinched and dark at the base, 7–14 days after germination

Likely Causes

Damping off (Pythium or Rhizoctonia spp.) — fungal rot triggered by wet, poorly ventilated germination conditions
Overwatering or trays left sitting in standing water

What to Do

1.Toss the affected tray — there's no recovering damped-off seedlings
2.Start fresh with a sterile seed-starting mix, not garden soil or old potting mix
3.Run a small fan near your germination setup and water only when the surface is dry to the touch

Leaves develop gray, powdery coating, usually starting on older foliage in mid to late summer

Likely Causes

Powdery mildew (Erysiphe cruciferarum) — common on brassica-family plants like stock, especially when nights cool and humidity rises
Dense planting that restricts airflow

What to Do

1.Remove and bag the worst-affected leaves — don't compost them
2.Thin plants or stake sprawling stems so air can move between them
3.Apply a dilute neem oil spray (2 tsp per quart of water) every 7–10 days once you spot early signs

Plants push full, leafy stems but no flower spikes, even past day 70

Likely Causes

Nights staying above 60°F, preventing the cool-period vernalization that Matthiola incana needs (45–55°F nights) to initiate bloom
High-nitrogen fertilizer pushing vegetative growth at the expense of flowering

What to Do

1.Start seeds indoors in February so plants get 6–8 weeks of cool nights before summer heat arrives
2.Switch to a phosphorus-forward fertilizer (a 5-10-10 works) once plants reach 6 inches tall
3.Treat stock as a cool-season crop — plan for fall or very early spring bloom, not midsummer

Frequently Asked Questions

How long do Katz Lavender Blue flowers last in a vase?▼

Katz Lavender Blue blooms typically last 7-10 days in a vase when kept in cool water (65-70°F) or refrigerated at 35-40°F. Change water every 2-3 days and trim stems at an angle to maximize vase life. For dried arrangements, properly air-dried flowers retain their appearance and fragrance for several months.

Can I grow Katz Lavender Blue in containers?▼

Yes, Katz Lavender Blue grows well in containers. Use well-draining potting soil in a pot with drainage holes. Place in a location receiving 4-6+ hours of full sun to partial shade daily. Container growing allows easier control of moisture and soil conditions, making it suitable for patios, balconies, and indoor spaces with adequate light.

What does Katz Lavender Blue taste like?▼

Katz Lavender Blue flowers have a peppery, clove-like flavor with floral notes. This distinctive taste makes them excellent as edible garnishes on salads, desserts, and drinks. The flowers add both visual appeal and a unique spice-forward flavor profile to culinary dishes.

When should I plant Katz Lavender Blue seeds?▼

Start seeds indoors 6-8 weeks before your last frost date, or direct sow after all frost danger has passed. This early-blooming variety reaches harvest in 90-100 days. For spring, early summer, and fall flowering as documented in trials, adjust planting timing to target desired bloom seasons in your climate.

Is Katz Lavender Blue good for beginners?▼

Yes, Katz Lavender Blue is ideal for beginners—it's rated as an easy variety requiring minimal care. It needs full sun to partial shade (4+ hours daily) and performs well across seasons. Important note: this variety produces one flowering stem per plant, so avoid pinching, which will stop blooming.

Why does pinching terminate flowering on Katz Lavender Blue?▼

Katz Lavender Blue is a one-cut series variety, meaning each plant produces a single flowering stem. Pinching removes the growing tip that produces that solitary bloom, terminating the plant's flowering potential. To maximize blooms, allow the plant to grow naturally without pruning or pinching.