Most compost is low nitrogen. For perennials and shrubs they really don't need much, if anything, if the native soil is at least halfway fertile. When in doubt add some compost to the planting area (you can just lay it right on the soil) and unless your soil is really sandy that should be enough.

Compost. All of the nutrients in compost require that activity of the Soil Food Web to release which is why it is a soil amendment and not a fertilizer, but is the single best thing you can add to your soil along with other types of organic matter. In organic gardeneing we feed the soil not the plants and you need to get away from thinking of "fertilizers" and think more of soil health.