they are green, red, or brown
Catkins are the flowers of a willow.
The flowers of a willow tree are called catkins. There is no standard collective noun for catkins, but based on their natural formation you could use the collective noun a cluster of catkins.
nothing
Yes.
bright and cheerful
No, an aspen tree is part of the populus genus. Only the trees from the birch genus (Betulus) produced catkins as the male pollinating adaptation The aspen Populus tremula does produce catkins in late winter and early spring. They are long and grey.
how am i supposed to know
Willow and Alder.
Cats don't produce catkins. Catkins are slim, cylindral flower cluster with inconspicuous or no petals produced by some plants.
hazel
Catkins are also called aments
catkins