Lavandula × intermedia 'Grosso'

Tried and Trouble-free Recommended by 5 Professionals
Common Name: lavandin
Type: Herbaceous perennial
Family: Lamiaceae
Zone: 5 to 8
Height: 2.00 to 2.50 feet
Spread: 2.00 to 2.50 feet
Bloom Time: June to August
Bloom Description: Lavender
Sun: Full sun
Water: Dry to medium
Maintenance: Medium
Flower: Showy, Fragrant
Leaf: Colorful, Fragrant
Attracts: Butterflies
Tolerate: Rabbit, Deer, Drought, Dry Soil, Shallow-Rocky Soil, Air Pollution

Culture

Grow in average, dry to medium, well-drained, alkaline soil in full sun. Lavandin can be difficult to grow in the St. Louis area, primarily because of winter stresses and high summer humidity. Well-drained soils are required, particularly in winter. Root rot commonly attacks plants grown in poorly drained soils. Prefers a light, sandy soil with somewhat low fertility. Remove faded flowers to promote continued bloom. Prune to shape in spring after new leaves appear. Prune back to 8” in spring every 3 years to control plant size and to promote robust, new growth. High summer humidity in the St. Louis area is not appreciated. To combat high humidity, consider using rock instead of organic mulch. Not reliably winter hardy throughout USDA Zone 5 where it appreciates a sheltered location and winter protection.

'Grosso' does not produce viable seed.

Noteworthy Characteristics

Lavandin (L. angustifolia x L. latifolia) is a popular hybrid lavender for the herb garden. Although it is rarely used for culinary purposes, it is frequently used as an addition to sachets and potpourris. It is a semi-woody plant that typically grows in a shrubby mound to 2-4’ tall. Gray-green leaves (to 2 1/2” long and 1/4” wide) on square stems. Flowers appear in terminal spikes (to 4” long) in summer. Both foliage and flowers are highly aromatic. Leaves are evergreen in warm winter climates. Hybrid cultivars vary somewhat in habit, flower color, aromatic intensity and bloom time.

Genus name comes from the Latin word lavo meaning I wash in reference to a former use of the plant as an aromatic wash.

Hybrid designation means intermediate.

‘Grosso’ is a mounded, shrubby cultivar that grows to 2-3’ tall and features silver-green foliage and very fragrant lavender flowers in summer. Flower spikes are unusually large and plump for this cultivar, rising well above the foliage mound.

Problems

Susceptible to leaf spot and root rot. Plants may not survive in winter if soils are not well-drained and/or if temperatures dip below zero degrees without protective snow cover.

Garden Uses

This is a versatile garden perennial that should be considered for a wide variety of uses and not just relegated to a corner of the herb garden. Flowers and gray-green leaves provide mid-summer color and contrast to the perennial border front, rock garden, herb garden or scented garden. Can be particularly effective when massed. Also effective as an edger.