People should get out and garden in the coming days and weeks to make the most of a spring which "could be over in the blink of an eye", experts said.
The recent cold wet weather and weeks of cooler than average conditions means plants have remained in bud longer than normal, the Royal Horticultural Society said.
But with sunshine and warmer temperatures forecast, there is likely to be a short, intense burst of spring flowering, as everything from magnolias to cherry blossom and wood anemones reach their peak.
While the spring displays will be "magnificent", they could be over within days as summer flowers take over, the RHS said.
The society's chief horticulturalist Guy Barter said: "I would urge people to get outside into their gardens or visit green spaces this weekend as spring could be over in the blink of an eye and you really don't want to miss what's coming.
"Look out for daffodils - they are usually over by now, but later flowers are still stupendous; flowering cherries are at their best and with the rain holding off, will be looking sensational.
"Magnolias are flowering late, as are camellias and rhododendrons.
"Usually spring begins in March and lasts until mid-May, so this shorter, condensed spring will create magnificent displays in our gardens, public spaces and roadsides across the UK as everything flowers at once."
It is also a good time to start sowing seeds and preparing gardens for the coming season, which many gardeners have not yet managed to do with the cold, wet weather, he said.
And he had some words of reassurance for those gardeners who have not yet pulled on their wellies and got into the garden.
"Although it is good to sow seeds and plant in March, plants do little growing until April and peak growth does not occur until June, so there is no need to be downhearted as in all likelihood there will be little difference in summer flowering."