Larkspur · Hejiang, Sichuan, China
When to sow larkspurs in Hejiang
Main outdoor window
31 Dec - 21 Jan
The window this page is built around.
Timed from last spring frost
28 January
In Hejiang, on your chosen risk.
Ready to pick
31 Mar - 20 Apr
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 Hejiang
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.
Sow direct
31 Dec - 21 Jan
Four weeks before your last frost.
In flower
31 Mar - 20 Apr
Larkspurs through the year
Against the frost risk in Hejiang
Why these dates
Sow direct four weeks before the last frost, into cool soil - the seed germinates below 15C and often refuses above 18C, which is why late sowings fail. Do not start it indoors; the taproot makes transplanting unreliable. Chilling the seed in a fridge for a fortnight before sowing improves germination markedly.
Hardy to about -12C as a seedling, so autumn sowing works well in zone 7 and milder and produces plants twice the size of spring-sown ones. Collapses in humid heat and will not persist through a subtropical summer.
Seed packets and extension guides express timing as weeks either side of the last spring frost, because that is the only reference point that travels. Larkspurs are timed for direct sowing 4 weeks before it, and this page simply resolves those offsets against the frost date computed for Hejiang.
Hardiness is not the obstacle here. Hejiang is zone 9b, 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 325 days, against 90 to 110 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Hejiang
Other flowers to time
Growing larkspurs in Hejiang
When should I plant larkspurs in Hejiang?
Aim for 31 Dec - 21 Jan in an average year. If you would rather not gamble on the weather, wait until 25 Jan - 15 Feb - by then frost has finished in nine years out of ten.
When will larkspurs be ready to harvest in Hejiang?
Expect to start picking around 31 Mar - 20 Apr, based on 90 to 110 days to maturity from the planting date calculated for this location.
How much frost will larkspurs tolerate?
Hardy to about -12C as a seedling, so autumn sowing works well in zone 7 and milder and produces plants twice the size of spring-sown ones. Collapses in humid heat and will not persist through a subtropical summer.