Planting bare root apple trees

I've purchased several one year apple tree whips on MM106 rootstock, currently heeled-in in large pots, sitting in my greenhouse. I am hoping to create an orchard in part of my field, but being in West Wales we've had non-stop rain this winter and the field resembles a marsh with small ponds in several areas
I was hoping to get them planted out in March maybe, would this be too late? Also if the ground is going to get this wet every winter are they just going to rot away? It was quite dry when we viewed the property in October and there are no reeds in this field and not much in the way of creeping buttercup either so we thought it reasonably well-drained. I have chosen traditional Welsh varieties as I hoped they would be better suited to the wet & windy conditions we have here.
Any advice welcomed - just don't say move to somewhere drier
Thanks MW
Posts
Today is definitely too wet ... my herb garden is ankle deep in water
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
Thank you all, I shall keep my fingers crossed for a nice long dry spell over the next few weeks then!
Pansyface - my boot prints fill up within seconds, never mind a lunch break
I have heard that you can plant on a mound of soil about 1 foot high & 1 metre diameter - has anyone tried this? Would this be a normal planting mixture of soil & compost & should I add some gravel for drainage? We also have a lot of strong winds to contend with as we're not too far from the coast so I'm preparing to stake them well, but would they be less stable with roots above the ground level?
MW