Bud Blast

As you walk through peony gardens this year, you may notice that some mature peonies have fewer flowers than usual. If you look closer, you’ll notice that where flowers might be, there are smallish, brown buds no larger than peas. This condition is bud blast.

Bud blast this year is the result of weather stress. Unseasonably warm temperatures in March and April signaled the plants to start development, and they were well along when nine inches of snow fell in late April, followed by several heavy frosts in May. This sequence interfered with bud development, resulting in a lower than usual bud count.

Bud blast is the plant’s response to stress of any sort. It is most common in newly divided peonies, which had already set buds by the time they were divided and transplanted the previous fall. As the plant’s root-building clock was reset, the plant did not have the resources to develop the buds it had set, so its energy was directed to stem and foliage production, and the buds blasted.

As long as the blasted buds do not contract fungus or mold, they are harmless, and the plant will continue to develop normally and produce well at maturity, two or three years after division in most cases.

There can be a benefit to bud blast, however. When the plant is supporting fewer flowers, all its resources are directed to those flowers, which are often larger and more spectacular than usual, as in this Pink Hawaiian Coral, usually a semi-double flower (at left) but this year, also fully double (at right):