Unsure why your peonies aren’t looking their best? We reveal the 3 pruning mistakes that could be damaging your blooms.
The beautiful blooms and foliage of peonies make for a stunning display. But sometimes our best intentions at pruning can lead to flowers that under perform.
Instinct might tell you to prune them back ready for next year’s appearance, but according to experts who tell us they’ve never pruned a peony in 30 years, you could be getting it very wrong.
So, before you set to with your secateurs, here’s what the experts advise, and the mistakes you could be making.
When it comes to maintaining peonies we need to treat them differently to other plants. We spoke to Nick Swankie, gardener at the National Trust’s Benthall Hall in Shropshire, about how and when to prune peonies.
“Peonies are herbaceous perennials that all do pretty much the same thing,” says Swankie. “They all die back in the winter. They make tidy plants in an herbaceous border, and they don’t need a lot of work.”
Swankie makes peonies sound like the ideal plant, especially when he told us they don’t need pruning.
“In 30 years of gardening, I’ve never pruned peonies,” he says. “They die back in the autumn and all you need to do is gently remove the previous year’s growth.”
For this reason, Swankie describes peonies as a good all-rounder, as there is more to the plant than just the flower.
“As Alan Titchmarsh would say, they are a good ‘doer’, and the foliage is really pretty.”
“You get some herbaceous perennials, such as delphiniums that look a mess once they’ve finished flowering and you have to cut them back, but with peonies, even though they have a short flowering season, they are good throughout the year.”
While deadheading often encourages flowers to continue to bloom throughout the season, prompting good plant health and more flowers to flourish, this isn’t the case with peonies. Swankie explains that deadheading peonies won’t encourage further growth in the season.
“Peonies only flower once on the season’s growth that they’ve put out that spring. You should be able to see all the flower buds in the spring before they open and that’s your show for the year.”
However, in some cases, it’s worth removing the old flower heads.
“Some of the doubles can look messy when they get wet and can start to rot on the stem,” says Swankie.
“If that’s the case, it’s better for health hygiene to get rid of those, otherwise they can cause rot to run down into the main plant.”
When removing a flowerhead, Swankie recommends taking it from where the flower stem meets the first leaf – there should be about a 15cm (6in) gap between the two. Remember always to use a sharp pair of secateurs to give a clean, healthy cut.
In most instances, you won’t need to worry about deadheading the flowers unless any have started to rot and go mouldy, as once the flowers have finished, you’ll be rewarded with beautiful seed pods.
“Lots of people think that if you cut back peonies that they’ll come back again, but they won’t,” says Swankie.
“If you were to prune all the leaves off a peony in mid-summer, it won’t thank you. It won’t make any new flowers, and although it will probably return the following year, it won’t be very happy about it.”
However, you can reach for your secateurs once the first frost arrives.
Swankie says: “Cut the old leaves off the plant, compost them if you can and leave them alone. You don’t need to mulch them.”
When do peonies flower?
“The main season is late April right up until the end of June,” says Swankie. And because of the timing of their flowering season, he recommends growing them with roses.
“Peonies start a bit earlier and very often finish when some earlier roses have finished their first flush.”
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