Hartz® Groomer's Best® Extra Gentle™ Cherry Blossom Scent Whitening Shampoo™. Dog shampoo. Hartz® Groomer's Best® Whitening Shampoo™ for dogs brings out the natural brilliance of white, silver and light coats and reduces discoloration. Deep cleans for a healthy shine. Hartz® and other trademarks are trademarks of The Hartz Mountain Corporation. www.hartz.com.