What honey plants should you have to feed the bees at the start of next year?

Hello, I am in Brittany (north-west France), I have a large, fairly isolated piece of land with already quite a few fruit trees and plants which produce flowers from the month of April. But now, I would need plants that produce flowers from March onwards. Every year, I see bees coming out in March, but as there isn’t much to forage, I don’t see many afterwards during the year. A neighboring plot of land is a conventional agricultural field. This fall the farmer planted rapeseed there. Except every time the rapeseed comes into flower, all the bees go there and die because of the treatments. I want to help them by sowing flowers now to offer them an alternative. What do you advise me? The land is clayey, compact and hydromorphic, sloping and exposed to the west. So at the end of winter, the earth is damp, cold and it is often windy. In March, temperatures generally range between -1⁰C at night and 15 to 20⁰C during the day if the weather is clear.