How to Grow Grosso Lavender

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Grosso Lavender

Lavandula × intermedia 'Grosso'

herb

Grosso is a hybrid lavender cultivar prized for its large, fragrant flower spikes and robust growth habit. It produces abundant purple flowers perfect for cutting, drying, and essential oil production. This is one of the most commercially cultivated lavender varieties worldwide due to its yield and fragrance intensity.

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Example Grosso Lavender timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Grosso Lavender

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Grosso Lavender

    Around Jul 16

    ≈ 90 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Grosso Lavender dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours daily minimum (8+ hours preferred)
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Water: Low water needs once established. Water deeply but infrequently; allow soil to dry between waterings. Overwatering causes root rot. In summer, mature plants rarely need supplemental watering except in drought conditions.
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Spacing: 24 inches
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Days to maturity: 90-120 days to first flowering from transplant
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Planting depth: Surface sow or barely cover seeds; transplants at soil line

Soil

Type: Well-draining sandy loam or gravel-based soil
pH: 6.4-7.5
Amendments:
Perlite or coarse sand (30-40% by volume) Compost (light application) Avoid heavy amendments that retain moisture

Growing Zones

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Thrives in zones 5-9, with best performance in zones 6-8

5a 5b 6a 6b 7a 7b 8a 8b 9a 9b

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Growth Stages

1

Seedling

3-4 weeks

Tiny cotyledons emerge, followed by fine, needle-like true leaves. Growth is slow initially.

Provide bright light, excellent drainage, and minimal watering. Use seed-starting mix amended with perlite. Keep soil moist but not wet.

2

Vegetative

6-10 weeks

Plant develops bushy, compact growth with fine, gray-green foliage. Stems elongate and become woody at base.

Maintain excellent drainage. Water sparingly once established. Full sun is critical. Begin light pinching at 6 inches to encourage branching.

3

Flowering

6-8 weeks (June-August in most zones)

Dense, long flower spikes (8-12 inches) emerge from branch tips. Flowers open from bottom to top, creating a gradient of purple hues.

Deadhead spent flowers to encourage continued blooming. Water during extended drought. Increase air circulation to prevent fungal issues.

4

Peak Bloom

2-3 weeks

Plant reaches maximum flower production with multiple thick spikes fully open and at fragrance peak.

This is the ideal harvest window for cut flowers or essential oil distillation. Flowers are most potent in late morning after dew dries.

5

Dormancy/Hardening Off

Fall through early spring (varies by zone)

After flowering, foliage may yellow slightly. Plant transitions to slower growth. Wood becomes fully lignified for winter survival.

Reduce watering further. Do NOT fertilize. Prune lightly in fall if needed, but avoid heavy pruning before winter. Mulch with gravel in zones 5-6.

Companion Planting

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Plant with:

Avoid planting near:

Hydrangeas Azaleas Blueberries Other acid-loving plants Plants requiring frequent watering

Common Pests

  • Handpick or use row covers during flowering. Remove and destroy infested flower buds. Yellow sticky traps can monitor populations.

  • Increase humidity with early morning misting. Use insecticidal soap spray. Improve air circulation with pruning.

  • Spray with water jet to dislodge. Use insecticidal soap or neem oil. Attract beneficial insects with diverse plantings.

  • Prevent through excellent drainage and avoiding overwatering. Remove affected plants immediately. Amend soil with perlite and sand.

  • Usually minor damage; handpick if severe. Bacillus thuringiensis (Bt) spray can be used as last resort.

Uses

🍳

Culinary flavoring and infusions

Culinary

Dried Grosso lavender flowers add floral notes to honey, sugar, baked goods, and herbal tea blends. The flowers are less intensely perfumed than English lavender, making them suitable for gourmet cooking. [source]

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Aromatherapy and essential oil

Medicinal

Grosso lavender has elevated linalyl acetate and linalool content, making it excellent for distilled essential oil used in aromatherapy, stress relief, and sleep support. Commercial-grade essential oil producers favor this cultivar for yield. [source]

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Cut flower and dried arrangements

Household

The long, sturdy flower spikes make Grosso lavender ideal for fresh cut flower arrangements and long-lasting dried flower crafts, wreaths, and decorative bundles. [source]

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Sachet and potpourri making

Craft

Dried flowers retain fragrance for months and are traditionally used in lavender sachets, linen closet fresheners, and fragrant potpourri blends. [source]

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Pollinator attraction

Wildlife

The abundant nectar-rich flowers attract honeybees, bumblebees, butterflies, and other beneficial pollinators, supporting garden ecosystems and improving pollination of nearby crops. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Harvest flower spikes when 75% of flowers are open, typically mid-to-late morning after dew dries for maximum fragrance and essential oil content. Cut stems 8-10 inches long just above the woody base. Peak harvest is usually mid-summer. For drying, hang bundles upside-down in a warm, well-ventilated space (70-85°F) away from direct sunlight for 2-3 weeks. Store dried flowers in airtight containers away from light.

Fun Facts

  • 🌱 Grosso lavender was developed in France and is the most widely cultivated lavender variety for commercial essential oil production, accounting for a significant portion of the global lavender oil supply.
  • 🌱 The name 'Grosso' means 'large' in Italian, referring to the notably large flower spikes that can reach 12+ inches in length—much longer than typical English lavender.
  • 🌱 Lavender has been used for over 2,500 years, with evidence of cultivation dating back to ancient Egypt, Phoenicia, and Rome, where it was valued for perfumes, medicine, and linen preservation.

Gardening Terms

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