Douglas iris (Pacific Coast iris) Iris douglasiana
Douglas iris (Pacific Coast iris) (Iris douglasiana) is an evergreen perennial flowering plant in the Iridaceae family, native to Coastal grassland and woods of California and southern Oregon. It grows 30–60 cm (12–24 in) tall and 40–80 cm (16–31 in) wide, wants part sun to part shade and low water, and is hardy to about -15 °C (5 °F). Space plants about 40 cm (16 in) apart.
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Douglas iris (Pacific Coast iris) at a glance
| Type | Perennial flowering plant, evergreen |
|---|---|
| Family | Iridaceae |
| Mature height | 30–60 cm (12–24 in) |
| Mature spread | 40–80 cm (16–31 in) |
| Spacing | 40 cm (16 in) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 5.5–7.5 |
| Cold hardiness | About -15 °C (5 °F) once established (roughly USDA zone 7) |
| Heat stress | Likely above about 34 °C (93 °F) |
| Flowering | from about April for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Moderate |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Coastal grassland and woods of California and southern Oregon |
| Common in gardens of | 🇺🇸 United States, 🇬🇧 United Kingdom, 🇳🇿 New Zealand, 🇦🇺 Australia |
Is Douglas iris (Pacific Coast iris) toxic?
- People: mildly toxic
- Cats: mildly toxic
- Dogs: mildly toxic
- Parts: rhizomes, leaves
Iris rhizomes contain irritant compounds; cattle avoid it in pastures.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Douglas iris (Pacific Coast iris)
No well-documented helpful pairing. Group it with plants that like part sun to part shade and low water.
Questions about Douglas iris (Pacific Coast iris)
- How far apart should I plant Douglas iris (Pacific Coast iris)?
- About 40 cm (16 in) apart, centre to centre. A mature plant spreads 40–80 cm (16–31 in).
- Does Douglas iris (Pacific Coast iris) need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Douglas iris (Pacific Coast iris) need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Douglas iris (Pacific Coast iris)?
- It tolerates about -15 °C (5 °F) once established, roughly USDA zone 7.
- When does Douglas iris (Pacific Coast iris) flower?
- From about April for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Douglas iris (Pacific Coast iris) poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs mildly toxic; for people mildly toxic. Iris rhizomes contain irritant compounds; cattle avoid it in pastures.
- What grows well with Douglas iris (Pacific Coast iris)?
- There is no well-documented companion pairing for Douglas iris (Pacific Coast iris). Group it with plants that like the same sun (part sun to part shade) and water (low).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- Calscape: California native plants, California Native Plant Society
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
Notes and assumptions
- A California native of the chaparral and foothills: it grows through the mild, wet winter and rests in the dry summer, when it should be left unwatered once established.
- Clumps of tough, glossy, evergreen sword leaves and veined flowers of lavender, purple, cream or yellow in spring. Native peoples made strong cord and fishing nets from fibres in the leaf edges.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Bearded iris Iris germanica
- Japanese iris Iris ensata
- Siberian iris Iris sibirica
- Dutch crocus Crocus vernus
- Gladiolus Gladiolus x hortulanus
- Freesia Freesia refracta hybrids
- Montbretia (crocosmia) Crocosmia x crocosmiiflora
- African iris Dietes grandiflora