The agave and aloe plants are succulents with fleshy, pointed leaves and a sculptural quality. Both provide a dramatic focal point in a garden. They are admired not only for their attractive form, but for their easy upkeep and drought tolerance. Though they appear superficially similar, there are many differences between the two plants. Agave is used for rope, tequila and a sugar substitute. Aloe is used for lotions and gels.
Though both agave and aloe are native to desert regions, they come from different areas of the world and different families in the plant kingdom. Agave is from the Agavaceae family and is native to Mexico. It is hardy in U.S. Department of Agriculture zones 8 to 10. Aloe, a member of the tree lily family known as Aloaceae, is native to parts of Africa and Arabia. It is hardy in zones 9 and 10.
Agaves range from 6 inches to 10 feet tall. The smallest is the Agave parviflora, which has sharp pointy leaves with curled fibers on the ends. The Agave mapisaga, on the other end of the spectrum, grows 10 feet feet tall and wide. There are more than 300 species of aloe, ranging from 2 inches across to tree height. Aloe vera, often grown as a houseplant and kept in the kitchen, contains a gel that helps heal minor burns. Larger aloe, such as the 50-foot-tall Aloe bainesii, has ''a grotesquely thickened trunk and tapering branches that make it look like a character out of a Dr. Seuss story,'' according to ''The Book of Outdoor Gardening.''
Many varieties of aloe have warmly colored red-orange, yellow or white flowers that replenish themselves throughout the plant's life. Aloe marlothii, for example, has side-leaning flowers that resemble red-hot flames blowing in the wind. It blooms year-round. A few agaves have flowers, but most of these bloom only once in the entire life of the plant. Queen Victoria agave is one flowering variety of agave. It blooms only after the plant has lived a decade or more and only in summer.
The leaves of the aloe and agave may look similar, but they are actually quite different. The agave has a fibrous leaf, with a vascular system of fibers running the entire length of each leaf. These fibers are used to make rope and string. The leaves often last the entire life of the agave. Aloe, on the other hand, has leaves with a gelatinous interior. Fibers are not present. Another difference is the leaf margin. Agave has distinct, sharp teeth on its margin, with a line of demarcation. Aloe has what appear to be teeth, but are actually just elongations of the leaf without any line of demarcation.