Arguably the most popular of our herbs, basil form is characterized by the square stems of its mint relatives and by flowers in the axils of the leaves or in very loose spikes. A general gardeners’ description of the basil genus is very difficult because of the great variety of leaf size, plant size, colors, and scents. But its flowering nature makes it quite attractive to beneficial insect visitors to our plantings.
There are an amazing 64 species of basil, It is native to tropics and subtropics of the Old and New Worlds, especially Africa. Varieties may smell of anise, camphor, cinnamon, clove, eucalyptus/carnation, lemon thyme, or other scents. All will cross readily within a particular species. The more popular and readily available basils include sweet, specialty fragrant (cinnamon, lemon and Thai/anise), purple-leaved, bush, and miniature or dwarf.
Basil is often used as a companion plant for tomatoes. Although some gardeners claim that basil can improve the growth and flavor of tomatoes, this is more folklore than science, according to the American Herb Society. One good reason to plant basil and tomatoes together is for convenience. Both plants have similar growth requirements, and their complementary flavors make close proximity a boon for harvesting. The insider’s trick to growing basil is to wait before transplanting it to the garden. Those who are patient enough to wait for nights above 60F and days that are long and sunny with temperatures in the 80s and above will be rewarded with thunderous growth. Similarly, those who insist on trying to sustain basil on a windowsill through the winter are sure to be disappointed.
A fine and reliable resource for the curious herb grower is Basil: An Herb Lover’s Guide by T. DeBaggio and S. Belsinger.