The hazels are displaying catkins including this one which grows beside Middle Walk.
A northern hemisphere genus Corylus (or hazel) contains 17 species of trees and shrubs. Many are grown for the male catkins produced in winter, and some are grown for their attractive purple foliage and their twisted stems. C. avellana is valued for its supple stems which are used in the production of hurdles and garden supports, and this species also produces the hazelnut. C. maxima is a more robust species, hence the specific name maxima. It originates from southern Europe and reaches up to 6m in height and produces catkins to 7cm in length. The fruits, or filberts in this case, are enrobed in husks twice their length. In the selection ‘Purpurea’ the foliage is a deep purple, and the catkins are purple-tinged.