Check out yellow leaves on rhododendrons and azaleas.
Some plants absorb excess nitrates or oxalates from the soil and store them in plant tissues. Toxicity problems can occur in animals which feed on these plants.
A list of recommended trees and shrubs in Oregon, good for controlling erosion.
Differences between processed and organic fertilizers are explained in this article.
OSU Extension publications show how to grow several kinds of berries, fruit trees, roses and native plants in Central Oregon.
Wild lilac is drought tolerant and needs no fertilizer