The gardens' wildlife and environment recording coordinator for the phenology project, Sandra Bell, said spring flowers have caught up and in some cases overtaken last year's blooming times - despite the worst snowfall for 20 years in February. Crocus, daffodils and snowdrops were later than last year to bloom as they were covered in ice and snow. But violets, magnolias and spring blossom trees such as wild pears and hawthorns are all flowering as early as ever before.
This shows climate change is no myth, said Bell. But she said that there may be a sting in the tail for gardeners. "Once cold weather lifted, everything moved forward but flowers could be hit by late frost as in 2008. If the cold had lasted it would have been better for flowers," she said.
The Met Office said spring this year is likely to be cooler than last year, with overnight frosts possible throughout March.
Dog's tooth violet flowered on 11 March this year, two days ahead of its 2000-2008 average of 13 March. Bell said: "Winter cold almost tricked it but now it's racing away and flowering earlier than is average for the decade."
She added: "Despite the cold weather - meaning early flowers were late - flowering has still moved forward 10 days since the 1950s and seven days since the 1980s because of climate change."
The phenology project at Kew notes the flowering patterns of more than 100 plants and has records going back 50 years. The information is fed into a nationwide study looking into the effects of climate change on nature.
Wild pear (Pyrus pashia) bloomed on 10 March. Bell said: "Despite the cold weather, it opened quite early. People are saying because snowdrops and daffodils were later than the past couple of years it kicks ideas of climate change into touch. But when you look at the figures this is still early flowering compared to two or three decades ago."
Bell expects magnolias to flower in the next couple of weeks ahead of Easter, and blackthorn, hawthorn, ash and oak could burst into colour by the end of March.
Bell said: "Very early plants are later, but slightly later material is slightly earlier."
- Snowdrop (Galanthus nivalis): 11 days late
- Winter aconite (Eranthis): 18 days late
- Narcissus pseudonarcissus: 16 days late
- Crocus tommasinianus: 10 days late
- Dog's tooth violet flowered on 11 March this year, two days ahead of its 2000-2008 average of 13 March.
- Wild Himalayan pear (Pyrus pashia) flowered on 10 March, which is mid-range compared to 2000.
- Purple plums (Prunus cerasifera pissardii) flowered in early March this year, which is the same as last year.
- Magnolia flowering expected on 20 March, like last year.
- Blackthorn/hawthorn/ash/oak will all be out by the end of the month, which is earlier than the decade on average.