When to Plant Lavender in Collinsville, Oklahoma (74021)

Location

Collinsville, Oklahoma

ZIP Code

74021

USDA Zone

Last Frost

Friday, April 10, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Friday, January 30, 2026

Transplant Outdoors

Friday, April 24, 2026

Based on last frost Friday, April 10, 2026 · Zone 7a

Pro tip: Start Lavender seeds indoors 10 weeks before your last frost date, then transplant outdoors around Friday, April 24, 2026.

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🌿 Plant Details

Scientific Name Lavandula angustifolia

Days to Maturity 90 days

Mature Height 18-36"

Spread 24"

Type Shrub

Fruit Size N/A

☀️ Growing Requirements

☀️

Sun

Full Sun (6+ hours)

💧

Water

Low (drought tolerant once established)

↔️

Spacing

24" apart

🌱

Planting Depth

0.125" deep

Seeds typically germinate in 14-21 days

Ready to Plant Lavender in Collinsville?

Get your seeds now so they're ready by Friday, January 30, 2026.

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🤝 Good Companions

TomatoBrassicasRoseSage

🤝

Full Companion Planting Guide for Lavender

See which plants help Lavender thrive, which to keep away, and raised bed layout tips →

🛠️ Supplies You'll Need

🌱 Seed Starting Trays 🪴 Seed Starting Mix 💡 Grow Lights 🌡️ Heat Mat 🪵 Raised Garden Bed 🌍 Vegetable Garden Soil 🛠️ Hand Trowel Set 🚿 Watering Can

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Common Lavender Varieties

Popular cultivars to look for at your local nursery or seed supplier.

Hidcote

english

Compact English lavender with deep violet flowers; one of the most fragrant varieties.

Munstead

english

Hardy English lavender that flowers early and is reliably cold-tolerant to Zone 5.

Vera

english

Classic large English lavender cultivar producing abundant oil for culinary and aromatic use.

Phenomenal

lavandin

Heat- and humidity-tolerant hybrid that thrives in climates where English lavender struggles.

Provence

lavandin

Tall French lavandin with very fragrant blooms; widely grown for essential oil production.

Common Lavender Problems

What to watch for — and how to fix it before it spreads.

🐛

Pests

Spittlebug (Froghopper)

Nymph hidden in a frothy "spit" mass on stems; causes distorted growth at affected nodes.

Fix:

Blast off with a strong water jet; usually not serious enough to need chemical control.

Aphids

Rare on lavender but occasionally found on tender new growth in spring.

Fix:

Strong water spray; plants typically outgrow light infestations without intervention.

🍂

Diseases

Root Rot (Phytophthora/Pythium)

The #1 killer of lavender — caused by overwatering or poorly drained soil; leaves gray and mushy stems at the base.

Fix:

Plant in fast-draining soil or raised beds; never water on a schedule — only when truly dry.

Botrytis (Gray Mold)

Gray fuzzy mold on stems and flowers in humid conditions or when plants are overcrowded.

Fix:

Prune heavily each spring to open up the center; improve airflow; remove dead flower heads.

Shab (Phomopsis)

Causes rapid die-back of individual branches; gray discoloration of wood under bark.

Fix:

Prune affected branches back to healthy wood; sterilize tools between cuts.

💡

Common Mistakes

Overwatering

Lavender is a Mediterranean drought-lover; wet roots are fatal.

Fix:

Water deeply but infrequently — every 2–3 weeks in summer once established; zero supplemental water in fall/winter in wet climates.

Planting in clay or rich soil

Lavender thrives on neglect in poor, well-drained soil; rich soil causes lush growth that rots easily.

Fix:

Amend with grit or perlite; plant in a raised bed with 50% native soil + 50% coarse grit.

Not pruning after bloom

Unpruned lavender becomes woody and open, flopping apart and producing fewer flowers each year.

Fix:

Cut back by 1/3 immediately after flowering; never cut into old gray wood — it won't regrow.

🌾 Seed Saving Guide

🟡 Moderate

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Let flower spikes dry fully on the plant before harvesting.

Processing

Strip seeds from dried spikes, winnow to remove chaff. Seeds are small and germination is slow.

Seed Viability

Up to 2 years when stored cool, dark, and dry.

Pro Tip

Cold-stratify seeds for 4–6 weeks to improve germination rates — without stratification, germination is erratic.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 8 plants of Lavender. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Lavender in Collinsville, Oklahoma? +

In Collinsville (Zone 7a), start Lavender seeds indoors around Friday, January 30, 2026 and transplant outdoors around Friday, April 24, 2026.

What is the last frost date for Collinsville, Oklahoma? +

The average last spring frost date for Collinsville, Oklahoma (ZIP 74021) is around Friday, April 10, 2026. This is based on NOAA climate normals for USDA Zone 7a.

How long does Lavender take to grow? +

Lavender typically matures in about 90 days from transplanting. In Collinsville, that means you can expect harvest around Friday, April 24, 2026 plus 90 days.

Should I start Lavender indoors or direct sow in Oklahoma? +

Lavender should be started indoors 10 weeks before your last frost date. In Collinsville, that means starting around Friday, January 30, 2026.

📚 More Lavender Planting Guides

🗺️

Lavender in Oklahoma

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 7a Lavender Guide

All cities in your zone · Avg dates

→

Other Plants for Collinsville

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Growing Lavender in Zone 7a

Lavender (Lavandula angustifolia) is a popular garden vegetable. In Collinsville, Oklahoma, which is in USDA Hardiness Zone 7a, you should start seeds indoors around Friday, January 30, 2026.

Your average last frost date is Friday, April 10, 2026. Plan to transplant your Lavender seedlings outdoors around Friday, April 24, 2026, about 2 weeks after your last frost date.