Far fewer snowdrops have been spotted by the end of the first week of February than last year.
The harsh winter has delayed early signs of spring, from snowdrops to frogspawn, according to sightings by the UK public.
But experts said the early hold-up caused by the bitterly cold December meant the rest of spring was likely to be "thundering" through in a rush in the coming months.
According to sightings reported to Nature's Calendar, a scheme which is run by the Woodland Trust, far fewer snowdrops, lesser celandine, hazel flowers and nesting rooks had been spotted by the end of the first week of February compared to last year.
There had been fewer than 300 sightings of snowdrops by 9 February, the Woodland Trust said, compared to 1,265 by that date last year.
The average date for spotting the first snowdrops is 4 February, according to Nature's Calendar, which uses 2001 as the baseline year because temperatures were very close to the long-term average that year.
Tim Sparks, founder of Nature's Calendar, which allows the public to report signs of the seasons across the country and help experts gain an accurate picture of how temperature changes are affecting nature, attributed this year's slow start down to the coldest December in 100 years of records.
"It was that cold month which has delayed flowering of things like celandines and snowdrops," he said.
But with fairly average temperatures experienced in January, the cold winter is not likely to delay the rest of spring, with bluebells, wood anemones and the leafing of oak trees expected to occur on time.
And because spring has been held up until now, events could unfold rapidly – unless there is another cold snap.
"We expect these things thundering through now, I think it's going to come through very rapidly," he said.
"Things will come on in much of a rush because they've been held back.
"By the time we get to hawthorn and bluebells, later spring events, they're going to be the usual time or could even be earlier," he suggested.
To mark the beginning of spring, the Woodland Trust, along with the National Trust, Wildlife Trusts and the RSPB, are helping people find their way into the woods to see the tell-tale signs of the new season.
A new VisitWoods website maps nearly 14,000 woodlands across the UK, allowing people to put in their postcode and find their nearest publicly accessible woods.
