Over the past week, I've been enjoying the spring weather by working in the pecan grove. Today, I collected terminal branches from several trees to illustrate the variation that occurs in time of budbreak between pecan cultivars. The photo below shows the stage of bud development for six pecan cultivars.
Greenriver buds were the most advanced with new leaves primed to unfurl. In sharp contrast, Hark buds were just starting to swell with their out scales recently split open.
When folks look at variation among pecan cultivars they often try to make generalizations in terms of northern pecan cultivars vs. southern cultivars. However, the earliest bud breaking cultivars shown above (Greenriver and Yates 68) are widely planted northern pecans. Lakota and Kanza are USDA creations that contain genes from both a southern cultivar and Major (a northern cultivar). Gardner and Hark are open pollinated seedlings of unknown parentage. From my experience, I have noticed an equal amount of variation in bud development among the native pecan trees that populate the Neosho River bottoms.
The timing of bud development has one important ramification. Trees that break bud early are more often damaged by late spring frosts. Over the years, I can clearly remember Greenriver buds suffering frost damage. However, with cold enough temperatures, all stages of green tissue on pecan trees can be injured.