I planted three peonies last fall and all grew flower buds this spring. One peony has grown quite a few stems, but the buds aren't getting bigger. We were really careful to plant them no more than 2 inches below the surface. One of the peonies has flowers now opening even after an incident of it catching some drift from a weed killer. I took the buds off a second plant that caught the weed killer so the plant would put its strength into defeating the spray.

What do you suppose the problem with the buds not growing on the third plant? Could this be typical of the first spring for new plants? This peony didn't catch any weed spray drift.