Crown imperial · Hanam, Gyeonggi-do, South Korea
When to sow crown imperials in Hanam
Main outdoor window
16-30 Sep
The window this page is built around.
Timed from last spring frost
12 April
In Hanam, 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 Hanam
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
16-30 Sep
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 Hanam
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 Hanam instead of forwards from its start.
Hardiness is not the obstacle here. Hanam is zone 6b, comfortably inside the range this crop is rated for, so an established plant should come through an average winter without protection.
The median frost-free season here is 199 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.
Nearby
Crown imperials in places close by
Also in Hanam
Other flowers to time
Growing crown imperials in Hanam
When should I plant crown imperials in Hanam?
Aim for 16-30 Sep in an average year. If you would rather not gamble on the weather, wait until 5-19 Sep - by then frost has finished in nine years out of ten.
When will crown imperials be ready to harvest in Hanam?
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.