Purple Alder buds and male willow flowers bursting with life yesterday in West Sussex at Wakehurst.

Alder

 Alder is monoecious, which means that both male and female flowers are found on the same tree.  More info' at https://www.woodlandtrust.org.uk/visiting-woods/trees-woods-and-wildlife/british-trees/a-z-of-uk-native-trees/alder/

Willows are dioecious (Greek: διοικία "two households") which means that it has distinct male and female individual plants.  Above the male flowers, which are loved by bees but not on this cold day.