A bulbous perennial of the Iridaceae family, this cultivar of Crocus chrysanthus is named after the famous Dutch nursery Van Tubergen, established in Zwanenburg, which produced a large number of horticultural crocus selections in the 20th century. The type species originates from the Balkans and Turkey, where it colonizes rocky lawns and open mountain slopes.
The coloring of 'Zwanenburg Bronze' is one of the most original in the chrysanthus group: the outer tepals have a dark bronze-brown dorsal side with purplish, almost metallic reflections, which contrasts sharply with the inside of the flowers, a warm and bright orange-yellow. This opposition between the dark, bronzed exterior and the bright interior is particularly striking at the time of the flowers' progressive blooming in the sun. The stamens are yellow, the stigmas bright orange. The foliage is narrow, linear, dark green with the characteristic white median line of the genus.
In its natural habitat, the species blooms from February to April depending on the altitude. In cultivation, 'Zwanenburg Bronze' blooms from February to March, among the first colors of the season.
It requires, like its congeners, a very well-drained, light and poor soil, in full sun, with a respected summer drought period. It integrates happily into rock gardens, gravel gardens, and trough compositions.