Dichelostemma congestum, Ookow or Forktooth Ookow, is endemic to the west coast of the USA and Canada where it grows in well-drained soils in full sun on grassy meadows, open foothill woodlands, prairie and rocky sagebrush slopes. Its tall scape bears an inflorescence of tightly packed lavender-mauve flowers giving it a superficial resemblance to an Allium. Like all Dichelostemmas (and Alliums!) it appreciates a well-drained substrate, ideally rather sandy or gritty so that the bulbs remain dry after its summer-flowering and when it goes into dormancy until the following Spring.

An undemanding plant, Dichelostemma congestum can be left to its own devices where it will slowly clump-up, forming many new bulbils every year and gradually naturalising. Its only real requirement is that it should have no water after it has flowered. That is not always easily accomplished in the UK, hence the need for a very well-drained gritty soil.