'Grosso' lavender (Lavandula x intermedia 'Grosso') is a hybrid variety that is a cross between English lavender (Lavandula angustifolia) and broadleaf lavender (Lavandula latifolia). It has both excellent heat and cold tolerance, plus boasts huge flower heads and a rich fragrance.
Include a more heat-tolerant English lavender hybrid in your landscape by planting ‘Grosso’ lavender. This lavender hybrid brings an improvement to traditional English lavender by blending cold hardiness with heat tolerance. ‘Grosso’ lavender also brings flowers that have larger heads, a darker purple hue and intense fragrance.
In botanical-speak, ‘Grosso’ lavender is Lavandula x intermedia ‘Grosso’. That “x” in the name reveals that ‘Grosso’ is a hybrid, the result of breeding two different lavenders. In this case, the parents are English lavender (Lavandula angustifolia) and a Portuguese lavender known as spike or broadleaf lavender (Lavandula latifolia).
Quite a few English lavender hybrids have these plant parents. Collectively, the hybrids are known as lavandins. The list includes ‘Grosso’, ‘Provence’, ‘White Grosso’ and ‘Hidcote Giant’. Lavandins are well-known in gardening circles for their strong garden performance and stems that are covered with long, gray-green leaves that are roughly twice the size of English lavender leaves. These hybrids also stage a heavy flower show.
‘Grosso’ lavender fits this description, opening an impressive number of flowers about midsummer. After the first heavy flush of blooms, plants send up additional flower wands throughout summer. ‘Grosso’ lavender flowers are so prolific and laden with essential oils that it’s the primary commercial variety grown for producing lavender oil.
In the home garden, ‘Grosso’ lavender blooms are favorites for crafting, with flower stems being gathered for lavender wands and bouquets. The strongly scented blossoms make wonderful additions to sachets and potpourris. The purple blooms of ‘Grosso’ lavender not only offer a deeper violet hue, but they’re contained in a bract that’s also purple (instead of green, like other lavenders). That makes these flowers even more desirable for craft purposes.
The rich perfume that ‘Grosso’ lavender blooms offer also works well in culinary applications. Use ‘Grosso’ flowers as you would any other culinary lavender to season desserts and savory dishes, as well as teas and spreads.
‘Grosso’ flower stems are elegantly long, extending far above the mound of silvery leaves. Clip stems of faded flowers to put the foliage in the spotlight. ‘Grosso’ lavender grows to form a mound that’s roughly 24 to 36 inches tall and wide at maturity. The plants tend to be compact, which makes them an ideal choice for a hedge or driveway edging. Just allow plenty of elbow room for the flower stems.
Like other lavenders, ‘Grosso’ thrives in full sun in well-drained, even rocky or sandy soil. This lavandin hybrid tolerates cold and summer humidity, surviving in regions where traditional English lavender cannot. Despite its sturdier nature, ‘Grosso’ won’t survive if it’s shaded or even crowded by other plants. Give it good air flow for best growth. Prune after flowering to shape the plant.