At the end of Watership Down, in the Epilogue covering
Hazel's peaceful death,
just before this happens, he has a final dream which is something about "rain and elder bloom":
One chilly, blustery morning in March, I cannot tell exactly how many springs later, Hazel was dozing and waking in his burrow. He had spent a good deal of time there lately, for he felt the cold and could not seem to smell or run so well as in days gone by. He had been dreaming in a confused way -- something about rain and elder bloom -- when he woke to realize that there was a rabbit lying quietly beside him -- no doubt some young buck who had come to ask his advice.
What, if anything, does this signify? Is there some symbolism in elder bloom or in rain, something to make either of them a particularly apt thing to appear in the last dream of Hazel's life?