Annual scabious · Philadelphia, Pennsylvania, United States
When to sow annual scabious in Philadelphia
Main outdoor window
31 Mar - 28 Apr
The window this page is built around.
Timed from last spring frost
14 April
In Philadelphia, on your chosen risk.
Ready to pick
29 Jun - 29 Jul
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 Philadelphia
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.
Start indoors
17 Feb - 17 Mar
Eight weeks before your last frost, under cover or on a windowsill.
Sow direct
31 Mar - 28 Apr
Two weeks before your last frost.
Plant out
7 Apr - 5 May
One week before your last frost.
In flower
29 Jun - 29 Jul
Annual scabious through the year
Against the frost risk in Philadelphia
Why these dates
Sow indoors eight weeks before the last frost and plant out a week before it, or sow direct two weeks before. Pick or deadhead every few days: this is a plant that stops the moment it is allowed to set seed, and keeps going for three months if it is not.
Hardy to about -8C, so young plants take a light frost and autumn sowing works in zone 8 and milder. Keeps flowering through the first autumn frosts.
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. Annual scabious are timed from 8 weeks before that frost for an indoor start, with planting out 1 weeks before it, and this page simply resolves those offsets against the frost date computed for Philadelphia.
Hardiness is not the obstacle here. Philadelphia is zone 7a, 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 202 days, against 90 to 120 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Philadelphia
Other flowers to time
Growing annual scabious in Philadelphia
When should I plant annual scabious in Philadelphia?
Aim for 31 Mar - 28 Apr in an average year. If you would rather not gamble on the weather, wait until 9 Apr - 7 May - by then frost has finished in nine years out of ten.
When will annual scabious be ready to harvest in Philadelphia?
Expect to start picking around 29 Jun - 29 Jul, based on 90 to 120 days to maturity from the planting date calculated for this location.
How much frost will annual scabious tolerate?
Hardy to about -8C, so young plants take a light frost and autumn sowing works in zone 8 and milder. Keeps flowering through the first autumn frosts.