Plant in full sun to light shade. Drought tolerant and cold hardy to at least 15 ° F. A great container plant or focal point specimen in the garden and on older plants the bottom leaves can be trimmed off to expose the trunk. Best to plant back away from a pathway; the leaves are not sharp but are rigid enough to be able to poke someone in an eye once they get to this height and leaf margins can slice like a paper cut.

Dasylirion longissimum species comes from the Mexican states of Hidalgo and Queretaro. The name for the genus comes from the Greek words 'dasys', meaning "dense" , "rough" or "shaggy" and 'lirion' meaning "lily" likely in reference to the rough leaves of some species. The specific epithet means "the longest" in reference to the extremely long leaves of this species. Also known at the Longleaf Sotol, this plant was long been included in the Agave family (Agavaceae) but is now considered to be with Nolina and Beaucarnea in the Nolinoideae subfamily within the huge Asparagus family, the Asparagaceae.

The scientific name of this plant has gone back and forth between Dasylirion longissimum and Dasylirion quadrangulatum. Generally these name have long been regarded as synonyms with Dasylirion longissimum, described in 1856 by the French botanist Charles Lemaire, considered to be the oldest valid name, while Dasylirion quadrangulatum was described in 1879 by the American botanist Sereno Watson. More recently these plants have been determined to be two separate taxa that vegetatively look the same, but Dasylirion longissimum, the more southern occurring species from the Mexican states of Hidalgo and Queretaro, flowers later in summer and fall with a spindle shaped inflorescence widest in the middle, while the more northerly species, Dasylirion quadrangulatum, from Tamaulipas, southern Nuevo Leon and northern San Luis Potosi, tends to flower earlier in the spring with a conical shaped inflorescence widest at its base. Since these plants were long considered synonyms, with seed collected somewhat indiscriminately, it is hard to know which plants are in gardens until they bloom. Rarely does a nursery plant flower and though we know that some of our older plants have previously flowered and these match best with Dasylirion longissimum, we cannot say the commercial seed purchased since had been the same and so might be either species. We feel this is consistent with plants sourced at other nurseries growing these narrow unarmed long leafed Dasylirion plants, so feel there is no guarantee which species one is likely to end up with. Fortunately, both species look very much the same and visibly the differences are minor, so this should not be an issue for most, except those who maintain well documented botanical collections. There is a bit more about this on the Ruth Bancroft Garden's Dasylirion Page. We have grown this interesting and attractive plant at our nursery since 1988 and also have long also grown the attractive gray foliaged Dasylirion wheeleri. 

The information about Dasylirion longissimum displayed on this web page is based on our research conducted in the nursery's horticultural library and from reliable online resources. We also include observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments we receive from others and welcome hearing from anyone with additional information, particularly if they can share cultural information that would aid others in growing this plant.