Common Name: poor knights lily
Type: Herbaceous perennial
Family: Xeronemataceae
Native Range: New Zealand
Zone: 10 to 11
Height: 2.00 to 3.00 feet
Spread: 6.00 to 13.00 feet
Bloom Time: May
Bloom Description: Red
Sun: Full sun to part shade
Water: Medium
Maintenance: High
Flower: Showy
Tolerate: Shallow-Rocky Soil
Culture
Best grown in evenly moist, loose, rich, very well-draining soil in full sun to part shade. Intolerant of overly wet, heavy soils. Prefers afternoon shade in climates with hot summers. This plant is a heavy feeder and requires regular applications of fertilizer during the growing season. Hardy in frost free Zones 10 and above. In its native habitat, this plant rarely experiences temperatures above 80°F and below 40°F. Some growers have found this plant to be tolerant of occasional light frost. Propagate by division or from seed. Seed germinates readily, but plant grow very slowly. Growing plants in small pots to create root bound conditions and only up potting when absolutely necessary may reduce the time clumps take to reach flowering maturity.
Noteworthy Characteristics
Xeronema callistemon, commonly called poor knights lily, is a herbaceous perennial endemic to the Poor Knights and Hen Islands off the northeast coast of New Zealand's North Island where it can be found growing on exposed, sheer rock faces around 1,000' above sea level. Mature clumps can reach up to 3' tall and spread by offsets to form a colony up to 13' wide in ideal conditions. In cultivation clumps are more likely to reach up to 6' wide. This is a slow-growing plant that may take 10-15 years to reach flowering maturity from seed. The foliage forms flattened fans and is iris-like in appearance (although this plant is not closely related to irises). The leaves are green-yellow in color, sword-shaped, and can reach up to 3' long and 2" wide. Sturdy, gently arching, 3' tall flowering stalks emerge from the foliage clumps in late spring bearing flowering racemes. The dense, bottlebrush-like, 4-20" long racemes are made of small, red flowers.
The genus name Xeronema means "dry thread", in reference to the upright filaments of the flowers which persist on the seedhead as it matures.
The specific epithet callistemon means "beautiful stamens" in reference to the stamens of this species which add to the bottlebrush-like appearance of the blooms.
The common name poor knights lily refers to the native range of this species.
Problems
Highly susceptible to root rot. Prevent infection by providing proper growing conditions and adhering to strict tool sanitizing protocols. If root rot does occur, remove and destroy all symptomatic parts of the plant and treat the remaining portion with a phosphonate based fungicide.
Uses
Mixed borders, rock gardens, coastal gardens, containers. Prefers to be root bound.