Pruning of shrub from photo. I think this shrub is a deutzia. Am I correct? How and when do I cut it back?
Thank you for contacting the Toronto Master Gardeners.
Your plant is a Deutzia sp. This shrub grows best in full sun to partial shade. It is very adaptable to both dry and moist growing conditions, but will not tolerate any standing water. It is not particular as to soil type or pH.
This plant produces beautiful star shaped flowers in the spring. Pruning should be done soon after flowering to avoid removing any of the current season’s flowers. If you prune them too late after flowering, then they will not have enough time to produce their new stems – which will be the flowering stems for the next year.
The following is from Gardenseeker.garden “Pruning is carried out by taking out all of the flowered stems – pruning Deutzia back by about one third of their previous length. So, each stem that has the faded flowers on, should be cut back, leaving around two thirds of the stem on the shrub.
Together with this, Deutzias respond to heavy pruning of around one in three of their stems – right back to – or near – ground level. This will encourage new basal shoots, which will soon grow to full length and provide a succession of healthy shoots for following years. Each year – at pruning time – cut back your Deutzia plant a further third of the old stems to ground level. This type of basal pruning will ensure that you will always have a vigorous Deutzia shrub that will not get too top heavy, and it will always be clad with foliage down to or near ground level.”
Pruning the Unprunables is an excellent article from Fine Gardening that discusses three different methods of pruning this shrub.