HI @my-tiny-garden
Good to hear from you again on this gardening forum!
Pruning Spirea can be tricky, especially given how much conflicting garden pruning information is online. Luckily, I've grown all kinds of Spirea for decades, so I can give you first-hand experience on the best time and way to prune Spirea.
When to prune Spirea?
The best time to prune Spirea is late winter as they are a deciduous shrub. January and February here in the UK is the best time, but avoid frost as this can slow down the healing process of newly cut branches. The buds tend to form in spring, not winter, so don't worry about removing potential flowers, unlike Forsythia and Camelia, which should always be pruned after flowering.
The exact timing can vary based on factors such as the spirea variety and exact geographical location. Generally, spirea shrubs produce flower buds on new growth, so pruning in late winter or early spring can encourage vigorous growth and abundant flowering later in the season
You can lightly trim a Spirea after it has flowered, but any proper pruning should be done in winter, in my experience.

How much to cut off Spirea?
Aim to remove no more than 1/4 of your Spirea at any one time. This is because they are relatively slow to recover from pruning. They are an average growing rate shrub, so they don't respond well to really heavy pruning.
Cutting the Spirea conservatively will create a better, well-rounded shrub shape rather than a stumpy-looking spirea.
Can I cut my Spiraa back to the ground?
I wouldn't advise a hard prune of any Spirea. They don't recover quickly or respond well to being cut back to the ground.
Hope that helps!
Lee Garden Ninja
HI @my-tiny-garden
Good to hear from you again on this gardening forum!
Pruning Spirea can be tricky, especially given how much conflicting garden pruning information is online. Luckily, I've grown all kinds of Spirea for decades, so I can give you first-hand experience on the best time and way to prune Spirea.
When to prune Spirea?
The best time to prune Spirea is late winter as they are a deciduous shrub. January and February here in the UK is the best time, but avoid frost as this can slow down the healing process of newly cut branches. The buds tend to form in spring, not winter, so don't worry about removing potential flowers, unlike Forsythia and Camelia, which should always be pruned after flowering.
The exact timing can vary based on factors such as the spirea variety and exact geographical location. Generally, spirea shrubs produce flower buds on new growth, so pruning in late winter or early spring can encourage vigorous growth and abundant flowering later in the season
You can lightly trim a Spirea after it has flowered, but any proper pruning should be done in winter, in my experience.

How much to cut off Spirea?
Aim to remove no more than 1/4 of your Spirea at any one time. This is because they are relatively slow to recover from pruning. They are an average growing rate shrub, so they don't respond well to really heavy pruning.
Cutting the Spirea conservatively will create a better, well-rounded shrub shape rather than a stumpy-looking spirea.
Can I cut my Spiraa back to the ground?
I wouldn't advise a hard prune of any Spirea. They don't recover quickly or respond well to being cut back to the ground.
Hope that helps!
Lee Garden Ninja
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