TENDER PERENNIAL. Grows 1 to 2 feet tall. This long-stemmed beauty has the darkest blue-purple flower spikes of any of the French hybrid types. It is also the most cold hardy French hybrid lavender cultivar. A heavy bloomer, the flowers have a strong lavender fragrance with a hint of camphor. The calyxes cling tightly to the flowering stems when dried, making ‘Grosso’ an excellent choice as an everlasting flower or for use in lavender crafts.