Hymenocallis x festalis Zwanenburg - Spider Lily

The Hymenocallis festalis ‘Zwanenburg’ is a summer bulb as graceful as it is original, often called spider lily or Peruvian daffodil. Its large ivory-white flowers, with narrow petals curved around a fringed cup, are of extreme refinement in borders, containers, and summer cut flower arrangements. Its airy flowering deserves a prime location to be admired up close.

From the family Amaryllidaceae, the Hymenocallis festalis ‘Zwanenburg’ belongs to the group of hybrids of Hymenocallis × festalis, formerly classified among the Ismene. This horticultural group brings together bulbous perennials native to subtropical areas of America (notably Mexico, Peru, and Bolivia), prized for their large, fragrant white flowers, shaped like an arachnid lily.
The cultivar ‘Zwanenburg’, resulting from the cross-breeding between Hymenocallis narcissiflora × H. longipetala, was created and introduced in 1912 by the Dutch house Van Tubergen, which gave it the name of the estate "Zwanenburg". It is a bulbous perennial plant with deciduous foliage: the long, ribbon-like leaves, of a bright green, emerge in a rosette in spring; they reach 40 to 60 cm in length. They dry out completely after flowering. The plant forms a fairly tight basal clump, from which emerge between May and June sturdy flower stems, 60 to 80 cm tall depending on growing conditions. Each stem bears an umbel of 2 to 5 large white flowers, 12 to 15 cm in diameter, among the largest in the festalis group. The flower structure is characteristic: a central cup-shaped trumpet, finely dentate on the edge, surrounded by six long, narrow segments, curved backwards like filaments. The heart is washed with soft green or pale yellow. This flowering emits a delicate fragrance, with vanilla notes, more perceptible up close than from afar. The hardiness of this plant is between -7 and -10°C: in colder areas, it is grown in a pot or the bulb is dug up and stored dry, frost-free, during the off-season.

The cultivar is diffuse under several synonymous names in literature and commerce: Ismene × deflexa ‘Zwanenburg’, Ismene × festalis ‘Zwanenburg’ or even Ismene festalis ‘Zwanenburg’.

In the garden as in a pot, the Hymenocallis festalis ‘Zwanenburg’ benefits from being placed near pathways to enjoy its sculptural flowers. In a large container, it can be paired with a dark and airy dahlia ‘Twyning’s After Eight’ or a blue agapanthus ‘Northern Star’, which highlight the whiteness of its flowers. In a sunny border, plant its bulbs among a few clumps of graceful grasses like Pennisetum orientale ‘Karley Rose’. In mild climates, a border mixing Hymenocallis, Salvia guaranitica ‘Black and Blue’ and a few clumps of ornamental tobacco ‘Lime Green’ creates summer scenes of real elegance and highly classy, fragrant bouquets.

The genus name Hymenocallis comes from Greek and evokes the "beautiful membrane" formed by the central crown of the flowers, a detail that already explained their success in botany collections in the 19th century.