Thyme is a small, robust shrub with small, aromatic leaves, native to the Mediterranean basin. It grows freely on the hot, arid hillsides of its home region, where it has far more flavor than it will ever reach in cooler regions. Wild thyme tends to be woody and sparse. The cultivated varieties have more tender stems and are bushy; there are hundreds of varieties of thyme, each with a slightly different aroma, and they also tend to cross species.