Astelia chathamica has arching silvery leaves, up to 6.5 ft (2 m) long. The flowers are cream, with male and female flowers on separate plants (dioecious). The fruits are bright orange.
Astelia chathamica is found in wet, peaty soils in the Chatham Islands, New Zealand. The form Silver Spear is said to differ little from the species. There are 25 species of Astelia, 13 are endemic to New Zealand. These plants have been assigned to the lily family (Liliaceae), or more recently to its own family (Asteliaceae).