How to Grow Grosso Lavender

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Grosso Lavender

Lavandula angustifolia 'Grosso'

shrub

Grosso is a premium lavender cultivar prized for its exceptionally large, fragrant flower spikes and vigorous growth habit. This French lavender variety produces abundant purple flowers and is one of the most commercially valuable lavender cultivars for both ornamental and essential oil production.

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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

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

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

Growing Conditions

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Sun: Full sun, 6-8 hours minimum daily; prefers 8+ hours for best flowering
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Water: Low water needs once established; drought tolerant. Water moderately during establishment (first 6-8 weeks), then reduce. Overwatering causes root rot. Allow soil to dry between waterings.
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Spacing: 18-24 inches
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Days to maturity: 90-120 days to first flowers; fully mature in 2-3 years
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Planting depth: Plant transplants at same depth as nursery pot; barely cover seeds (1/8 inch)

Soil

Type: Well-draining sandy or gravelly loam; tolerates poor soils
pH: 6.0-8.0
Amendments:
Coarse sand or gravel for drainage Perlite if soil is heavy clay Minimal compost or organic matter

Growing Zones

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Zones 5-9; thrives in Mediterranean climates and well-drained soils

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

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Growth Stages

1

Seedling

4-6 weeks

Tiny leaves emerge with characteristic narrow, silvery-green foliage. Plants are fragile and slow-growing.

Keep soil barely moist, not wet. Provide bright light. Avoid overwatering. Thin seedlings to prevent damping-off disease.

2

Vegetative Growth

8-12 weeks

Plant develops bushy mounding form with increasingly dense, aromatic foliage. Narrow, gray-green leaves become more prominent.

Water sparingly; allow soil to dry between waterings. No fertilizer needed. Begin to reduce watering to encourage hardening off.

3

Pre-flowering

4-6 weeks

Plant reaches mature size and thickness; flower buds begin to form at stem tips in late spring.

Continue dry conditions. Do not fertilize; excess nitrogen reduces flowering. Ensure excellent drainage.

4

Flowering

6-8 weeks (June-July in Northern Hemisphere)

Large, dense purple flower spikes (up to 4 inches long) appear abundantly. Flowers are highly fragrant and attractive to pollinators.

Deadhead spent flowers to encourage reblooming. Water only during extreme drought. Do not fertilize.

5

Dormancy/Maintenance

4-6 months

After flowering, plant enters rest phase. Foliage remains ornamental throughout fall and winter. In cold climates, growth slows considerably.

Prune lightly in fall or early spring to maintain shape and encourage bushiness. Avoid heavy pruning. No water needed unless prolonged drought.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Plants requiring frequent watering Moisture-loving plants like astilbe or hostas Nitrogen-fixing legumes that may overstimulate growth

Common Pests

  • Remove by hand; encourage beneficial insects. Rarely requires treatment.

  • Spray with water to dislodge. Use insecticidal soap if severe. Improve air circulation.

  • Prevent through excellent drainage. Remove infected plants. Avoid overwatering.

  • Improve air circulation. Remove affected leaves. Use copper fungicide if severe.

  • and

    Lavender's strong scent typically deters grazing animals. Use fencing if problems persist.

Uses

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Culinary flavoring and beverages

Culinary

Grosso lavender flowers can be used to flavor baked goods, honey, tea, lemonade, and desserts. The large flower spikes contain abundant edible petals with a floral, slightly sweet flavor profile. [source]

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Essential oil and aromatherapy

Medicinal

Grosso is renowned for high-quality essential oil production with strong linalool and linalyl acetate content, prized for relaxation, stress relief, and sleep support. The essential oil is used in aromatherapy, massage, and natural remedies. [source]

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Dried flowers and fragrance

Household

Dried Grosso flowers retain their fragrance for months, making them ideal for sachets, potpourri, drawer fresheners, and homemade household products. The large flower spikes are particularly attractive for dried flower arrangements. [source]

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Floral crafts and arrangements

Craft

The large, uniform flower spikes of Grosso are ideal for wedding arrangements, wreaths, crafts, and floral displays. They dry cleanly and maintain color well, making them a premium choice for dried flower work. [source]

🦋

Pollinator support

Wildlife

Lavender flowers are highly attractive to bees, butterflies, and other beneficial pollinators. Grosso's abundant, large flowers make it an excellent nectar source for supporting pollinator populations. [source]

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

Harvest Tips

Cut flower spikes in mid-morning after dew dries but before peak heat, when flowers are just opening to mid-bloom. Harvest flowers at peak bloom for drying (June-July in Northern climates). Cut stems 6-8 inches long, leaving at least 1/3 of plant's growth. Tie in small bundles and hang dry in dark, well-ventilated area. For essential oil production, harvest at first bloom. Can harvest 2-3 times per season on mature plants.

Fun Facts

  • 🌱 Grosso lavender is one of the most commercially valuable lavender cultivars worldwide, especially prized in France and Spain for essential oil production due to its high yield and superior fragrance quality.
  • 🌱 The name 'Grosso' means 'large' in Italian, referring to the cultivar's notably larger and more abundant flower spikes compared to other English lavender varieties.
  • 🌱 A single mature Grosso plant can yield 1-2 pounds of dried flowers per year, with each flower head containing dozens of tiny florets packed with fragrant essential oil.

Gardening Terms

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