English bluebell · London, England, United Kingdom
When to sow english bluebells in London
Main outdoor window
8-22 Oct
The window this page is built around.
Timed from last spring frost
14 April
In London, 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 London
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
8-22 Oct
Four to six weeks before your first frost, so roots form before the ground cools.
In flower
1 Apr - 31 May
English bluebells through the year
Against the frost risk in London
Why these dates
Plant in early autumn, 10cm deep, and buy from a cultivated source rather than lifting from the wild, which is illegal in much of its range. Never cut the foliage before it yellows. Establishment takes two or three seasons, and the first year often produces leaves alone.
Hardy to -25C. Needs cool moist summer shade and a real winter; it will not naturalise in a hot dry climate. Keep it well away from Spanish bluebells, which hybridise with it and swamp the true form.
English bluebells 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 London instead of forwards from its start.
London sits in zone 9a, 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 219 days, against 150 to 190 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in London
Other flowers to time
Growing english bluebells in London
When should I plant english bluebells in London?
Aim for 8-22 Oct in an average year. If you would rather not gamble on the weather, wait until 19 Sep - 3 Oct - by then frost has finished in nine years out of ten.
When will english bluebells be ready to harvest in London?
Expect to start picking around 1 Apr - 31 May, based on 150 to 190 days to maturity from the planting date calculated for this location.
How much frost will english bluebells tolerate?
Hardy to -25C. Needs cool moist summer shade and a real winter; it will not naturalise in a hot dry climate. Keep it well away from Spanish bluebells, which hybridise with it and swamp the true form.