Rhubarb turning yellow and dying?

I planted 3 rhubarb roots earlier this spring in a raised bed composed of about half native soil (=clay) and half compost. In the past two weeks, the leaves have been turning blotchy yellow, then brown, and dying. The stalks have also been going limp and dying as well. They have had adequate water (it usually rains a lot in the spring here) and I have beans and peas planted right next to them that are thriving. Help!

Thanks
pam