I find this article interesting because it explains the different stages of bud development.
Beth Ann A. Workmaster, Jiwan P. Palta, and Teryl R. Roper
Department of HorticultureUniversity of Wisconsin-Madison College of Agriculture and Life Sciences, Madison, WI 53706
Cranberry researchers and growers typically use some sort of ad hoc terminology to refer to the growth stages of the bud in the springtime. This can be based on measurements of the changes in size of the bud and the subsequent growth, or on a description of their physical attributes, or morphology. It would be useful to standardize this terminology to aid in communication between and among researchers and growers. We have recently begun a research program at the University of Wisconsin-Madison to study cranberry frost survival. Our goal is to better advise growers about the freezing temperatures to which the plants will survive at different times of the year.
After taking close-up photographs of the buds of the uprights for several weeks in the spring of 1995 we established a visual continuum of spring bud development and growth. As expected, bud hardiness changed dramatically over the course of the spring, from being able to withstand temperatures colder than -4°F when dormant to surviving only temperatures just below freezing after the new uprights elongate. Thus, at different points along that bud developmental continuum significant changes in hardiness occur. In order to assess these changes more specifically we have been working on developing a useful set of terminology for these different bud stages.
3. Cabbagehead. Substantial swelling of the bud has occurred. Bud scales are opening, but still enclose the new growth. As the name implies, this stage is named for the bud’s ressemblance to a head of cabbage. Many buds have lost much or all of their red pigment. When viewed from the side, buds appear pointy and lengthened, in preparation for the emergence of the new growth.