Nolina nelsonii growing at the corner of Inner Campus Dr. and Whitis Ave., the University of Texas at Austin
The gardens surrounding the BIO Building and the Teaching Greenhouse have several interesting plants donated in years past by students and professors of the former Botany Department. One of them, a 7-foot tall member of the Asparagus family, is currently attracting the attention of passers-by with its spectacular inflorescences. Nolina nelsonii Rose (Nolinoideae, Asparagaceae) is a native of the xerophytic shrubland covering the mountains and canyons surrounding the town of Miquihuana, central Tamaulipas, Mexico where it grows more than 3 meters tall.
Despite an architectural similarity, this plant is not immediately related to Yucca as some might guess. Asparagaceae is a cosmopolitan clade encompassing more than 2500 species that includes the edible asparagus but also hyacinths, agaves and yuccas. In 1996 UT botanists Dr. David Bogler and Dr. Beryl Simpson researched the phylogenetic relationships of the genera related to Agave using nuclear ribosomal DNA and showed that the genera Beaucarnea (including Calibanus), Dasylirion and Nolina, share a common ancestor. These three share the characteristics of long strap-like, fibrous leaves with or without spines along the margins and rosette-like habits on inconspicuous or well-developed trunks. Beaucarnea, Dasylirion and Nolina are mostly dioecious (single sex inflorescences in separate individuals) and native to the southwestern United States, Mexico and Guatemala. More closely related to Nolina than agaves or yuccas are African, Asian and European genera, including cultivated plants such as Aspidistra (iron plant), Liriope (grape hyacinth), Sansevieria (snake tongue) and Convallaria (lily-of-the-valley).
White male flowers of Nolina nelsonii.
Because of its compact habit, silvery-green leaves, drought tolerance, and resistance to subfreezing temperatures, Nolina nelsonii has become a popular plant in the horticultural trade in the Austin area. It is one of those plants that you plant and can forget about it once established. Inflorescences of Nolinoideae are terminal that is, the vegetative shoot ends with the formation of the flowering shoot. Unlike most agaves, bromeliads or a few palm trees that die when they flower, nolinas resume growth from one or more side shoots near the inflorescence area that keeps the main stem growing. Our N. nelsonii plant on the SW corner of the greenhouse and facing Hogg Memorial Auditorium is a male individual that has flowered before and been pruned, hence the multiple shoots on its trunk. Two smaller species of Nolina are familiar to Texans under the moniker beargrass. Our local species N. texana S. Watson and N. lindheimeriana (Scheele) S. Watson differ from N. nelsonii in forming rosettes rather than elongated trunks and have bright green foliage, but like N. nelsonii they are a great addition to xerophytic gardens and one of them can be seen by the turtle pond.
I encourage you to visit the greenhouse grounds and observe this beautiful species and its large greenish inflorescence. It will be a while before it flowers again.
Dr. José Panero is Associate Professor and Associate Director of the Billie L. Turner Plant Resources Center.
