Plant of the Month July 2009

Iris hookeri

Iris hookeri growing in the wild; photo by Todd Boland

Rare lavender form of Iris hookeri; photo by Todd Boland

Description and general information

This dwarf iris is essentially endemic to the Gulf of St. Lawrence region; coastal Newfoundland, Nova Scotia, Anticosti and Magdalen Islands the north shore of Quebec and southeastern Labrador. In its native haunts, it usually grows within reach of the ocean spray. The soil is often quite acidic with a high organic content. They also inhabit coastal sand dunes. Plants are somewhat variable in size, ranging from 10-30 cm. The flowers are generally a mid-blue but rarely you may encounter lavender forms or even white.

This plant has changed names several times in the past. While originally described as I. hookeri, it was later reclassified as I. setosa ssp. canadensis. Recently it was once more segregated back to I. hookeri. Iris setosa is essentially a Eurasian species which extends into Alaska. Plants are quite tall in comparision to I. hookeri but the flower form is quite similar.

Cultivation

This species is hardy into USDA zone 3 maybe even colder. Provide full sun and reasonably moist, organic-rich soil that is at least slightly acidic.

Bloom period

In Newfoundland, this species begins blooming in late June and throughout July. In more southern areas, they may bloom in April or May.

Propagation

Plants may be divided after blooming. They are also easily raised from seed but do require a stratification period of at least 6 weeks to maximize germination. Alternatively, you may sow the seeds in the fall and leave them outside for the winter. They will germinate quite freely come spring.

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