Plant Highlight: Agave potatorum
Our July 2004 plant highlight featured an Agave which we originally received as Agave verschaffeltii. Since this name is considered a synonym of Agave potatorum, our highlight gave this latter name for it. A. potatorum is normally a single-headed species, while our plant produced a modest number of offshoots to form a small clump. The rosettes of leaves were also smaller on our plant than is usual for A. potatorum, and its inflorescence was smaller. We therefore referred to it an atypical, offsetting form of the species. A visiting botanist from Oaxaca, upon seeing the plant, informed us that it is actually a different and relatively recently-described species, Agave isthmensis. Our October highlight features the true Agave potatorum.
Agave potatorum is an attractive small to medium-size species from southern Mexico. It is usually a solitary species, propagating itself by seed rather than by offsets or bulbils as many other species do. It is one of the most widespread species in the state of Oaxaca, and occurs also in the southern part of Puebla to the north of Oaxaca. In this region of Mexico, it is much used to make mescal, a distilled alcoholic beverage which is similar to tequila. From our point of view, it is a beautiful garden ornamental.
A. potatorum is the most northerly occurring species in the group Hiemiflorae. Most of the members of this group are found in Central America and Mexico’s southernmost state of Chiapas. Other members of this group are seldom seen in cultivation in California, and this may be due to their limited tolerance for cold.
The leaves of Agave potatorum are normally a beautiful bluish color, though light green forms of it are also known. The impressions of neighboring leaves, made before they unfurl from the plant’s center, leave attractive patterns embossed on the leaf surface. The margins bear crenellations topped with reddish or dark brown sharp teeth, and the tips are armed with a stout dark spine. The size of the rosettes is normally 2 feet (60 cm) or less in diameter, though larger specimens are sometimes encountered.
A.potatorum tends to flower in the fall or winter months, and the stalk rises to a height of about 10 to 20 feet (3 to 6 m). Short side-branches end in small clusters of greenish-yellow flowers. While the floral display is not very vivid, like many other species of Agave it is notable for its great height in relation to the size of the plant, and the sight of the rapidly-emerging stalk adds a dramatic vertical element to a garden. We have 2 plants now flowering at RBG, one of which already has open flowers. The second specimen has sent up its stalk, but has not yet commenced flowering.