Noah Mabey, senior gardener at Thornbridge Hall, claimed that May is “the best time” to start pruning back a few key plants but noted that “it has to be done carefully”. He noted that plants such as ribes (flowering currant), forsythia, spiraea and choisya can all be cut back now – but only lightly. To carry out this task, Noah said that you want to start by “deadheading spent flowers” and then “prune around a third of the older woody stems” – this keeps the plant healthy without overdoing it. Here are four key types of plants to get on with pruning before May comes to an end.
Tender perennials
Once frost risk has passed, May is the right time to cut back tender perennials such as penstemons, fuchsias and salvias.
Noah said, “These plants respond really well to a cut back after frost risk has gone. It encourages strong new growth and better flowering later in the season.
“I also recommend trimming any unusually long or ‘leggy’ stems, cutting back to a bud to encourage more controlled growth.
“I also advise gardeners to remove any reverted growth on variegated shrubs to maintain their colour and structure. It’s a simple job, but it keeps plants looking their best.”
Climbing plants
As climbing plants like honeysuckle grow, Noah instructed gardeners to tie in new stems and keep “deadheading to extend flowering”.
He said, “Try tying stems horizontally to encourage more flowering shoots and reduce wind damage.”
It’s also important to check anything growing against walls – fruit trees, roses or climbers – and gently untuck stems that may have slipped behind wires. Doing it now is much easier while growth is still soft.
Rhododendrons and wisteria
Rhododendrons are at their peak in May, but once flowering finishes, they should be deadheaded and lightly pruned.
Noah said, “Removing spent flower buds helps the plant put energy into next year’s blooms instead of seed production. Wisteria also needs attention after flowering.
“Once it has finished blooming, deadhead and shorten long shoots to encourage flowering spurs. If you’re still training it, now is the perfect time to tie in new growth.”
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