Adapted from the April e-newsletter from HydrangeasPlus®
Hydrangeas, as an example, do best with a balanced fertilizer. Kristin VanHoose, owner of HydrangeasPlus®, prefers the granular time-released kind that delivers nutrients to the plant over a three-four month period. Water breaks down the outside coating of the fertilizer slowly and nutrients don't dwindle out in the active spring growth season. Soil should be slightly moist when applying the granulated variety and keep the fertilizer off the foliage to prevent burn. When hydrangea leaves start showing through the leaf nodes, it's time for an application of time release fertilizer, according to Kristin.
If you prefer an organic or natural fertilizer alternative, your local garden center should be able to give you good advice (check the OAN’s online Retail Nursery Guide for garden centers near you).