Rosemary · Birmingham, England, United Kingdom
When to plant rosemary in Birmingham
Main outdoor window
15 Nov - 4 Apr
The window this page is built around.
Timed from last spring frost
18 April
In Birmingham, on your chosen risk.
Ready to pick
1 May - 31 Oct
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 Birmingham
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 out
15 Nov - 4 Apr
Any time the plant is dormant and the ground is neither frozen nor waterlogged: after leaf fall in autumn, or at the end of winter before growth restarts.
Harvest
1 May - 31 Oct
Rosemary through the year
Against the frost risk in Birmingham
Why these dates
Plant out after the last frost so the roots establish through a full growing season. Cuttings root readily in early summer, which is a faster and more reliable route than seed - rosemary seed germinates poorly and slowly.
Hardy to about -15C in free-draining soil, and considerably less in heavy wet ground. Drainage matters more than any temperature figure here.
Rosemary are planted once and then left in place, so there is no sowing offset to resolve. What matters in Birmingham is the shape of the year: this crop is dormant through the winter and is planted while it sleeps, any time between leaf fall in autumn and the restart of growth in spring, so long as the ground is neither frozen nor waterlogged. That is why the window below spans the cold months rather than sitting in the middle of the growing season.
Hardiness is not the obstacle here. Birmingham is zone 9a, comfortably inside the range this crop is rated for, so an established plant should come through an average winter without protection.
Do not expect a crop in the first year. A plant set out now should give its first worthwhile pick around year 1, and will then produce every year after that, which is what makes the planting decision worth getting right the first time.
Growing rosemary in Birmingham
When should I plant rosemary in Birmingham?
Aim for 15 Nov - 4 Apr in an average year. If you would rather not gamble on the weather, wait until 29 Oct - 29 Apr - by then frost has finished in nine years out of ten.
When will rosemary be ready to harvest in Birmingham?
Expect to start picking around 1 May - 31 Oct, based on 90 to 120 days to maturity from the planting date calculated for this location.
How much frost will rosemary tolerate?
Hardy to about -15C in free-draining soil, and considerably less in heavy wet ground. Drainage matters more than any temperature figure here.