Crown imperial · Qods, Tehran, Iran
When to sow crown imperials in Qods
Main outdoor window
21 Oct - 4 Nov
The window this page is built around.
Timed from last spring frost
18 March
In Qods, on your chosen risk.
Ready to pick
1 Apr - 31 May
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Qods
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.
Plant the bulbs
21 Oct - 4 Nov
Four to six weeks before your first frost, so roots form before the ground cools.
In flower
1 Apr - 31 May
Crown imperials through the year
Against the frost risk in Qods
Why these dates
Plant in early autumn, as early as the bulbs can be bought, and deep - 20cm. The bulbs have a hollow crown that collects water and rots, so plant them at a slight tilt or on a handful of grit. They resent disturbance and often skip a year after being moved.
Hardy to about -25C. The smell deters mice and voles, which is a genuine advantage in a garden where tulips get eaten. Needs cold winters and dislikes hot wet summers.
Crown imperials 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 Qods instead of forwards from its start.
Qods sits in zone 8b, 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.
The median frost-free season here is 260 days, against 160 to 200 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Qods
Other flowers to time
Growing crown imperials in Qods
When should I plant crown imperials in Qods?
Aim for 21 Oct - 4 Nov in an average year. If you would rather not gamble on the weather, wait until 6-20 Oct - by then frost has finished in nine years out of ten.
When will crown imperials be ready to harvest in Qods?
Expect to start picking around 1 Apr - 31 May, based on 160 to 200 days to maturity from the planting date calculated for this location.
How much frost will crown imperials tolerate?
Hardy to about -25C. The smell deters mice and voles, which is a genuine advantage in a garden where tulips get eaten. Needs cold winters and dislikes hot wet summers.