We recommend using Jirdon’s Tree and Shrub fertilizer. It is formulated specifically for trees and shrubs in the Rocky Mountain region. You should apply a light application around May 15, June 15, and July 31. If you are fertilizing less often shoot for May 15 and July 15. You don’t want to fertilize after the first part of August. You don’t want to push too much new growth late in the season. Bill’s Rose food can be used for roses and should be applied once a month until September.