Lavandula × intermedia 'Grosso' (Grosso Lavandin)
Lavandula × intermedia 'Grosso' (Grosso Lavandin)
Contents
Introduction & History
Grosso Lavandin is the commercial powerhouse of the lavender world — the single most widely grown lavender cultivar globally, covering thousands of hectares across Provence, producing more essential oil per plant than any other variety. This vigorous hybrid between English lavender and spike lavender combines the best of both parents: the fine fragrance of angustifolia with the robust productivity of latifolia.
History & Origin
A natural hybrid (Lavandula angustifolia × L. latifolia) selected in France by Pierre Grosso in the Valensole Plateau of Provence. Introduced commercially in the mid-20th century. It quickly dominated the Provençal lavender industry because its oil yield per hectare far exceeds that of true English lavender. The purple fields of Provence photographed by tourists are predominantly 'Grosso' lavandin, not true lavender.
Botanical Description
Large, vigorous sub-shrub growing 60–90 cm tall and 90–120 cm wide — significantly larger than English lavenders. Long, elegant flower spikes (8–12 cm) of violet-blue flowers on tall, graceful stems rise well above the silvery foliage. The plant forms a substantial, rounded mound. Leaves are broader and greyer than English lavender. The scent is rich and complex with more camphor than L. angustifolia.
Stem: Square (quadrangular) — diagnostic for Lamiaceae • Leaves: Opposite, decussate arrangement • Height: 75 cm at maturity • Spread: 90 cm • Foliage: silver-grey • Flowers: dark violet (summer)
Planting & Cultivation
Plant nursery-grown specimens in spring, spacing 60–90 cm apart (much wider than English lavenders). Full sun and well-drained, alkaline soil. Ideal for large gardens, mass plantings, and informal hedges. The large size means it's not suitable for small herb gardens. Plant where it has room to grow to its full 120 cm spread.
| Sun exposure | Full Sun |
| Soil pH | 6.5-8.0 |
| Spacing | 90 cm |
| Seed depth | 3–6 mm (surface-sow if light-dependent germinator) |
| Water needs | Low |
| Soil type | Well-drained, humus-rich loam; add perlite or grit for drainage |
Cultivation Details
Same conditions as English lavender but on a larger scale. Full sun, lean soil, excellent drainage, no fertiliser. The vigorous growth means plants fill their space quickly. Trim after flowering — remove spent spikes and 5–8 cm of leafy growth. Never cut into bare wood. The taller stems make commercial harvesting with machinery practical — hence its dominance in the industry.
Climate & Hardiness
Hardy to about −15°C (USDA zones 6–9). Slightly less cold-hardy than English lavender but more heat- and drought-tolerant. Handles hot summers better than L. angustifolia varieties. In zones 5–6, site carefully with south-facing exposure and excellent drainage. Ideal for Mediterranean, California, and similar climates.
USDA zones: 5-9
Minimum temperature: -18°C
Drought tolerance: Yes — established plants tolerate dry spells
Seasonal Care
Spring: trim winter damage; strong growth resumes. Summer: magnificent flowering in July — harvest at peak. After flowering: major trim. Autumn: no pruning. Winter: ensure drainage; protect in zone 6 with gravel mulch and fleece in extreme cold.
Propagation
By semi-hardwood cuttings only — 'Grosso' is a sterile hybrid that produces no viable seed. Take 10–12 cm cuttings in late summer, root in gritty compost. Cuttings are slower to root than English lavender (6–8 weeks). Layering of low branches is also effective. Commercial nurseries use mist propagation for volume.
| Method | Success rate | Time | Notes |
|---|---|---|---|
| Stem cuttings | 70–90% | 2—4 weeks | Softwood in spring, semi-ripe in summer; 8–12 cm |
| Division | 95%+ | Immediate | Split established clumps in spring or autumn |
| Seed | 50–80% | 14–28 days | Some require cold stratification; germination variable |
| Layering | 80–90% | 6–12 weeks | Pin low branch to soil; sever when rooted |
🌍 Distribution Map
Native origin: hybrid, France
Diseases & Pests
Same as English lavender — root rot, rosemary beetle, lavender shab. The greater vigour provides some resilience. Ceratocystis wilt is a serious disease affecting lavandin fields in Provence — it's spread by cicada insects and has devastated some plantings. Not typically an issue in home gardens.
Culinary Uses
Less preferred for culinary use than English lavender — the higher camphor content gives a slightly harsher, more medicinal taste. Usable in cooking but L. angustifolia varieties are superior for delicate dishes. 'Grosso' works better in robust preparations: lavender-infused marinades for grilled meats, lavender and rosemary combinations, and strongly flavoured baked goods where the camphor note adds complexity.
| Category | Pairing suggestions |
|---|---|
| Baking | Shortbread, scones, cakes |
| Preserves | Jelly, syrup, sugar |
| Cocktails | Gin botanicals, spritzers |
| Honey | Infused honey, dessert garnish |
Medicinal & Aromatherapy
The essential oil contains more camphor and 1,8-cineole than English lavender, making it more stimulating than calming. Lavandin oil is used in cleaning products, soaps, and industrial fragrances rather than fine aromatherapy. For true calming aromatherapy, L. angustifolia is preferred. 'Grosso' oil is excellent for muscle aches, decongestant blends, and household products.
| Compound | Properties |
|---|---|
| linalool | floral, calming |
| cineole | camphoraceous, expectorant |
| thymol | antiseptic, warm |
| carvacrol | pungent, antimicrobial |
| eugenol | clove-like, analgesic |
Container & Companion Growing
Container Growing
Possible but requires very large containers (40+ litres) due to the plant's size. Better suited to garden planting. If container-grown, use a large terracotta pot with very gritty mix. Full sun. The spreading habit is less elegant in containers than the compact English lavenders.
• Minimum pot size: 30–40 cm Ø, 15 L+
• Excellent drainage essential; add perlite
• Use free-draining potting compost with 20–30% perlite or grit
• Ensure drainage holes; stand on pot feet to prevent waterlogging
• Feed with dilute liquid fertiliser (half-strength) every 2–3 weeks in growing season
Companion Planting
Spectacular in mass plantings — the classic Provençal field look. Plant along driveways, boundaries, and large borders. Pairs with other drought-tolerant Mediterranean plants: rosemary, cistus, santolina, and ornamental grasses. The tall flower stems provide height contrast with lower herbs.
| ✓ Good companions | Roses, Brassicas, Fruit trees |
| ✗ Avoid planting with | Mint (invasive neighbour) |
Common Mistakes to Avoid
Planting too closely — 'Grosso' needs 60–90 cm spacing. Using it interchangeably with English lavender in cooking (the camphor note differs). Expecting the same compact habit as 'Hidcote' (it's twice the size). Not appreciating the difference between lavender and lavandin essential oils.
Harvesting & Preservation
Harvest when the lower quarter of flowers has opened for highest oil content. The long, uniform spikes are ideal for dried bundles and wands. Dries beautifully — hang in bundles for 2 weeks. The dried flowers retain their colour and scent well. For essential oil distillation, cut entire flowering stems and process immediately. One plant yields 3–5 times more oil than an English lavender plant.
• Time of day: Early morning, after dew has evaporated but before intense midday heat volatilises essential oils
• Growth stage: Just before flowering, when essential oil concentration peaks. Once flowers open, the plant redirects energy from leaf production
• Season: Summer
• Part harvested: Flowers
• Harvest rule: Never remove more than ⅓ of the plant at once; this ensures continued vigorous regrowth
• Technique: Cut stems cleanly above a leaf node with sharp scissors or secateurs. Tearing damages tissue and invites disease
| Method | Process | Shelf life | Best for |
|---|---|---|---|
| Air drying | Tie bundles, hang upside down in warm, dark, airy space | 6–12 months | Most herbs |
| Oven / dehydrator | Spread on trays, 35–45°C until crisp | 6–12 months | Fleshy-leaved herbs |
| Freezing (whole) | Blanch 5s, ice bath, pat dry, freeze flat on tray | 6 months | Basil, chives, parsley |
| Freezing (oil cubes) | Chop fine, pack into ice cube tray, cover with olive oil | 6 months | Any culinary herb |
| Herb salt | Layer herb and coarse salt 1:4, dry and grind | 12+ months | Rosemary, thyme, sage |
| Infused vinegar | Pack jar, cover with warm vinegar, steep 2–4 weeks | 6 months | Tarragon, dill, basil |
| Infused oil | Fill jar with dried herb, cover with oil, steep 4–6 weeks | 3–6 months | Rosemary, thyme, chilli |
Frequently Asked Questions
What's the difference between lavender and lavandin?
Lavandin (L. × intermedia) is a hybrid of true lavender (L. angustifolia) and spike lavender (L. latifolia). It's larger, more productive, and has a more camphoraceous scent. True lavender oil is finer and more expensive; lavandin oil is the workhorse of the lavender industry.
Are the purple fields of Provence real lavender?
Most are lavandin — specifically 'Grosso.' True lavender grows at higher elevations (above 600m) in smaller plots. The vast purple fields at lower elevations are commercial lavandin plantings.
Can I use Grosso for cooking?
You can, but English lavender (L. angustifolia 'Hidcote' or 'Munstead') is preferred for culinary use. Grosso has more camphor, which can taste medicinal in delicate dishes. It works better in robust preparations with strong accompanying flavours.
Seasonal Care Calendar
🌱 Spring (Mar–May)
Water: Light
Feeding: No feeding
☀️ Summer (Jun–Aug)
Water: Light
Feeding: No feeding
🍂 Autumn (Sep–Nov)
Water: Minimal
Feeding: No feeding
❄️ Winter (Dec–Feb)
Water: Minimal
Feeding: No feeding
The commercial lavender king — vigorous hybrid (60–90 cm tall, 90–120 cm wide) dominating Provence's purple fields. Highest oil yield of any lavender. Violet-blue flowers on long stems. Hardy to −15°C (zones 6–9). More camphoraceous than English lavender — better for products than delicate cooking.
Quick Reference: Lavandula × intermedia 'Grosso'
Key Principles: Right location, well-drained soil, regular harvesting to promote growth, and appropriate winter protection for tender species.