Gros Bleu

Lavender

Zone 9a Save Garden

🌱 365d to harvest Shrub

Breathe in the first rush of cool, resinous fragrance—Gros Bleu blooms with a bold, lavender-blue presence that feels almost velv…

Crop Dates

Milestone	Date
Start Indoors	Jan 9th
Last Frost	Mar 6th
Transplant / Sow Outdoors	May 1st
Harvest Begins	May 1st
Harvest Ends	Nov 26th

Crop Details

Trait	Value
Days to Maturity	365
Sun Requirements	Full Sun
Growth Habit	Shrub
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	60
Min Night Temp (°F)	40
Harden Off (days)	7

Recommended Companions

Thymus Vulgaris 'German Winter Thyme

Frequently Asked Questions

What pest or disease problem most often affects Lavandula × intermedia (Gros Bleu), and how can I control it?

Lavender commonly suffers from root/crown rot when the soil stays wet—symptoms include sudden wilting and blackening at the base. Plant Gros Bleu in fast-draining soil, avoid overhead watering, and water only when the top 1–2 inches are dry; in severe cases, remove the affected plant parts and replant in fresh, well-drained mix. If you see a persistent issue, also thin crowded growth for better airflow to reduce fungal problems.

How often should I water Lavandula × intermedia during its main growing season?

During the main growing phase, water deeply only when the top 1–2 inches of soil are dry, then let it dry out again before the next watering. In hot summer conditions this may be roughly 1–2 times per week, but the key is soil dryness rather than a fixed schedule; avoid frequent light watering that keeps roots wet. Mulch sparingly and keep mulch pulled back from the crown to prevent moisture buildup.

How do I tell when Lavandula × intermedia (Gros Bleu) is ready to harvest?

Harvest when the flower spikes are mostly formed and the buds are just starting to open—about 30–50% of the florets should be open for the best fragrance and color. Cut stems in the morning after dew dries, before the hottest part of the day, and avoid harvesting after the flowers fully turn brown. For long color, you can do a second light harvest after regrowth if plants stay healthy.

Breathe in the first rush of cool, resinous fragrance—Gros Bleu blooms with a bold, lavender-blue presence that feels almost velvety in the air. Its aromatic flower spikes rise on sturdy, upright stems, offering a richly textured harvest of deep-toned blossoms that dry beautifully for long-lasting scent. Grow Gros Bleu for a perennial showpiece that perfumes the garden year after year, ideal for sachets, potpourri, and fragrant bundles.

Sowing Tips

Transplant Conditions

Wait until soil reaches 60°F and nights stay above 40°F before moving outdoors. Harden off for 7 days first.

Expert Note

Start with a very light, fast-draining seed-start mix and avoid overwatering—lavender fails more from soggy roots than cold weather.