Phenology Is Key by Trees Are Key published on 2018-03-29T13:46:43Z Phenology Is Key Recently, we talked about spring tree care and mentioned a term you may not be familiar with. Phenology is the study of cyclic and seasonal natural phenomena. When do ash trees start to leaf out, when are the cherry blossoms at their peak in Washington DC? Join us this week as we explore why “Phenology Is Key” Species Spotlight This week's tree is beautiful and currently blooming in my yard in Central Texas. Carolina Laurelcherry, Prunus caroliniana, is a small native evergreen that fits in many yards.