Garden Q&A: What time of year should I prune hypericum?

Whether you're a gardening beginner or expert, Irish Examiner columnist Peter Dowdall has the answer to your questions

St John's wort (Hypericum perforatum).

QUESTION

I want to cut back/prune hypericum. When should I do this and not disturb this year's flowering?

ANSWER

There are various different species of hypericum and, in truth, it depends on the species that you are growing to answer this correctly. 

Hypericum perforatum, which is the species commonly referred to as St John's Wort, doesn’t need any pruning as it is herbaceous, meaning that it dies back for the winter. 

Hypericum calycinum, known as the rose-of-Sharon, is extremely vigorous and can be cut back hard each spring to keep it somewhat in check. 

One of the most commonly grown cultivated forms of hypericum is H. Hidcote which is less vigorous and makes a lovely summer flower addition to any garden. 

It is not always necessary to prune this cultivar either but if you do want to give it a light trim, do so in early spring. 

Cut it back before mid-March so that you don’t lose any of the current years blooms.

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