Allergy relief for my Grandpuppy?

First, let me start by sayin, "I hope this is posted in the right forum"?
Every year round this time my Grandpuppy (She's a black lab)starts to itchin really bad at the top of her tail area. She does this "Butt Bumpin" thing(for lack of better words)till she wears off most of her hair. I've took her to the vet in the past and they always give her a shot. But I was hopin there was some kinda natural cure I could use cause she really hates goin to the vet's. I called the vet and asked the nurse what kinda medicine it is they give her, but she said she had no idea and I'd have to ask the Dr. But the Dr ain't never called me back yet??? That was on Monday. Anyways, whatever is causin the allergies is something that comes at the end of June to the first of part of July.
If anybody out there has a suggestion or maybe knows what kinda plant she might be allergic to, it would really be great !!

Thanks A Heap,
LuLu and
Destiny the Itchy Pup
By the way,
she just turned 10
on May 1st
(she'll always be a pup to me) Tweet