Dutch iris · Oran, Oran, Algeria
When to sow dutch irises in Oran
Main outdoor window
not outdoors here
The window this page is built around.
Timed from last spring frost
no spring frost
In Oran, on your chosen risk.
First autumn frost
no autumn frost
The far end of the outdoor season.
The average last frost. Half of all years are later than this.
Step by step in Oran
Each window is a range, not a single day. Earlier in the range buys you a longer season; later in it buys you a safer one.
Dutch irises through the year
Against the frost risk in Oran
Why these dates
Plant in autumn, six weeks before the first frost, 10cm deep. In zone 5 and colder, plant in early spring instead, or mulch heavily - these are the least hardy of the common autumn bulbs. Lift and dry the bulbs after the leaves die back if your summers are wet.
Hardy to about -15C, appreciably less than a tulip, and the emerged spring leaves are damaged by a hard late frost even where the bulb survives. Mulch after planting where winters fall below -12C.
Dutch irises are anchored to the first autumn frost rather than the last spring one, so the planting window on this page counts backwards from the end of the season in Oran instead of forwards from its start.
Oran sits in zone 10b, which is milder than this crop wants, and a winter that never really arrives is its own problem. The dates below still describe the right time of year; the open question is survival rather than timing.
Also in Oran
Other flowers to time
Growing dutch irises in Oran
How much frost will dutch irises tolerate?
Hardy to about -15C, appreciably less than a tulip, and the emerged spring leaves are damaged by a hard late frost even where the bulb survives. Mulch after planting where winters fall below -12C.