Dasylirion quadrangulatum - Sotol

The Dasylirion quadrangularum, sometimes called the Quadrangular Sotol, is a tree-like succulent plant related to yuccas and agaves. It is much less common in cultivation than its close relative, the D. longissimum, to which it bears a strong resemblance. Its remarkably architectural silhouette truly enhances a dry garden, or even a terrace or patio when planted in a pot This fascinating plant bears numerous long, thread-like, non-prickly leaves radiating from the centre of the rosette, eventually forming a large sphere resembling a perfectly organised bouquet of fibre optics. Mature specimens develop a short and massive trunk and spectacularly flower with an immense floral spike that can exceed 3m (9 ft 10 in) in height. It is an easily cultivated plant in arid, poor, even limestone and rocky soil. Its hardiness mainly depends on soil drainage.

Dasylirion quadrangularum is a plant that can grow in low-lying areas of eastern Mexico and the southern United States. It can survive temperatures as low as -8°/-10C if planted in well-drained soil and exposed to winter rains. It can also tolerate long periods of drought during the summer. This plant belongs to the agave family and grows slowly in dry soil but faster in moist soil. It forms a dense ball when young, but as it matures, it becomes more graceful. It can grow up to 1m (3 ft 4 in) in height and 50cm (19.7 in) in diameter, with a trunk covered in old brown leaves. The crown of the plant is spherical, 80cm (31.5 in) to 1m (3 ft 4 in) wide, and made up of several hundred thin, flexible leaves that are medium green. Flowering occurs after 10 to 15 years of growth in summer. Small yellowish flowers densely pack a slender, upright spike that emerges from the centre of the plant. The spike often remains on the plant, even until winter. Male and female plants are distinct. Careful consideration should be given to the plant's placement, as its fragile root system, unlike agaves, does not tolerate disturbance and transplantation very well. This plant does not die after flowering, as a secondary bud on the central axis takes over. When watered during the summer, this dasylirion grows spectacularly.

The Dasylirion quadrangularum requires plenty of sunlight and well-draining, even poor and dry soil. It particularly dislikes heavy, waterlogged soils in winter. It is ideal on a large, arid slope, at the top of a large exotic or contemporary rock garden, or even near a swimming pool if the soil is well prepared to receive it. This plant will simply be magnificent when planted alone, accompanied by Cerastostigma plumbaginoides, Delosperma, or a dry meadow lawn called Zoyzia tenuifolia, the Mascarene grass. It can also be paired with agaves, Hesperaloe parviflora, prickly pears that are quite hardy (Cleistocactus strausii, Cylindropuntia imbricata), and equally spectacular and frugal shrubby aloes. It is well-suited for container cultivation, which provides protection from cold and humidity in winter.