The delayed spring could lead to a bumper crop of apples, strawberries, blackcurrants and gooseberries for gardeners this year, the Royal Horticultural Society (RHS) said.
Recent cold weather has held back the flowering of fruit trees and shrubs so they are less likely to be hit by the damaging effects of frost, with plants still at the more robust bud stage when they can withstand dips in temperature.
RHS chief horticulturist Guy Barter said: "Frost can seriously damage open flowers and baby fruitlets, but the risk of frost decreases the closer you get to June."
He said that if fruit trees flowered in February there would be "months and months of potential frosts to ruin the flowers", but later flowering - at the normal peak time of around April 26 for apples - reduced the risk of being hit by frosts.
And with cold weather forecast into the beginning of May, spring blossoms are likely to be a week late, pushing them closer to the frost-free period, he said.
"While that may not sound like a significant delay it can mean the difference between a bountiful harvest of fruit including apples and strawberries and an average or poor year," he said.
Some of the pear trees at RHS Garden Wisley, Surrey, flowered in February before cold weather pressed pause, making it likely they were damaged by frosts in recent weeks.
But around half the orchard's pears, which flower earlier than apples, are now just on the cusp of flowering and apple trees are budding.
Mr Barter said: "We were really worried earlier in the year that everything was going to be desperately early, now it's heading into being late."
But he added: "This cool weather can't go on forever. The sun's getting higher in the sky every week so sooner or later it's bound to be warm and the flowers will come out."
The RHS has data going back a century on flowering times and harvests from its Wisley orchard, covering hundreds of different varieties, which allows them to give advice on the best types of fruit trees and shrubs for gardeners to grow if they live in frost pockets.