'Italian Large Leaf' basil yields large Genovese-type leaves up to three inches long on plants that grow one to two feet tall and about a foot wide. Basil thrives in the sun but is not drought tolerant, so water regularly. As is true of many herbs, gardeners can harvest small amounts of basil by pinching the tips of stems for immediate use. This actually keeps the plant compact and bushy, forcing out even more leaves. Up to one-third of a plant may be harvested at once without impairing the plant's overall health.  Flower buds should also be pinched out to prolong leaf production, as the flavor tends to change (and not for the better) once flowers are allowed to grow.