Yucca whipplei

Yucca whipplei, sometimes called Hesperoyucca, is one of those quite extraordinary plants native to arid North American regions. Forming a dense yet graceful ball at ground level, adorned with long, tapered and stiff leaves, it eventually produces a unique yet spectacular flower spike. This spike is filled with numerous globular and waxy flowers, greenish on the outside and pendulous. This flowering marks the end of the life of the rosette, which ensures its longevity by developing numerous suckers. Reserve a prime location for this plant, which will bring an exotic colour and the breath of wide-open spaces to your decor. It excels in a dry garden or at the centre of a large rockery.

Native to the hills of California and Baja California, Hesperoyucca whipplei, just like evergreen ceanothus, is at home in the chaparral, a vegetation formation similar to scrubland. It is a low-altitude plant (from 0 to 300 m (0 to 984 ft)) that tolerates both long periods of drought and short freezes of about -15 °C (5 °F) at minimum temperature, in porous soil. It is a stemless rhizomatous plant belonging to the agave family, with rather slow growth, able to occupy more than 1 m (3 ft) of ground. Yucca whipplei forms a graceful, very dense ball, composed of numerous quite rigid leaves. Depending on the growing conditions, the leaves can reach 25 cm (10 in) to 1.15 m (4 ft) in length and 7 mm (1 in) to 2 cm (1 in) in width. They are linear, finely toothed along the edges, and end with a strong spine. Their colour is a soft greyish-greenish-blue. Flowering occurs after 5 years of growth, from June to August. In this species, the inflorescence is unique and emerges prominently from the mass of foliage. It rapidly develops at the top of a stalk measuring 3 m (10 ft) to 3.5 m (11 ft) in height and 70 cm (28 in) in width. Hundreds of bell-shaped flowers, about 3 cm (1 in) in diameter, open on this ramified panicle inflorescence. They are creamy white, washed with green or violet on the reverse side of the petals, and have a waxy texture. The fruit does not form in our temperate climates, in the absence of the plant's natural pollinator. It is a dry and winged capsule that splits open when ripe to release the seeds. The rosette of leaves dies after flowering, but new branches emerge at the base: this group of clones allows the plant to continue growing and reproducing.

In nature, Yucca whipplei often grows in the company of oaks and pines, on rocky hillsides with sparse woodland. In warm and dry regions, it can be showcased in the garden, emerging from rocks against a backdrop of evergreen foliage and prostrate shrubs like rosemary, creeping ceanothus, and kermes oak. It will find its place on a large arid slope, at the centre of an exotic or contemporary rockery, or even near a swimming pool, if the soil is well prepared to receive it. It is advisable to keep it slightly away from pathways and young children due to its sharp-pointed leaves. This plant will be simply magnificent as a standalone specimen, accompanied by a carpet of cerastium, Cerastostigma plumbaginoides, Delosperma, or even a dry meadow lawn such as Korean velvet grass (Zoyzia tenuifolia). It can also be combined with agaves, prickly pears, and hardy columnar cacti (Cleistocactus strausii, Cylindropuntia imbricata), as well as equally spectacular and frugal shrubby aloes. It can also be planted in a large pot on the terrace, accompanied by tall grasses, other yuccas, or a Cassia corymbosa, etc.