Winter flowers could be seen at Chelsea Flower Show in May for the first time after the coldest March for more than a century.
Garden designers are worried that their favourite flowers might not be ready for Chelsea Flower Show, which begins in six weeks time.
Garden designer and RHS assessor Andrew Fisher Tomlin tweeted: "Will there be irises at #rhschelsea flower show? Long range forecast says it'll be a cold April."
Iris and peony specialist Kelways is supplying 10 Chelsea gardens including Michael Balston, Chris Beardshaw, Jo Thompson, Flemings and Ulf Nordfjell.
Kelways director Dave Root said: "It’s the coldest March and Easter I’ve ever known. This year has been an incredibly slow start. I just hope they come up and everything grows like fury. Every year you think you have seen it all but failure is not an option because it is Chelsea and its going to be a lot of more work and a lot more."
"At the moment we’re looking at three weeks behind and at the moment we’re holding our nerve. On the good side, lots of plants that wouldn’t usually make Chelsea will.
Usually difficult to keep back for Chelsea are early peonies, brunnera and epimedium but they will be ok to be there this year. Even hellebores could make it. I don’t think they have ever made Chelsea before but they stand a chance."
Root said he would not know if signature Chelsea plant the iris would not flower in time until 21 days before plants start to show flower spikes. The 21-25 May show is almost sold out say the RHS.
Chrysanthemums Direct sales manager Martyn Flint said: "We’re three or four weeks behind. The March London RHS show didn’t look much different to the February show."
RA Scamp representative Adrian Scamp: "Even for us in Cornwall we’re still behind by a couple of weeks for the general bulk of the crop.
Hardy’s Cottage Garden Plants co-owner Rob Hardy: "We’re two or three weeks behind because of the cold. The good news is there’s moisture in the ground. This time last year there was drought. There’s so much desperation from gardeners just to get out there. This time last year it was 20 degrees C warmer than now."