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
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.
Yes.
bright and cheerful
Yes, the diamond-leaf willow (Salix eriocephala) does produce flowers. These flowers are typically catkins, which are elongated clusters that emerge in the spring before the leaves. The catkins are usually yellowish or greenish and can be either male or female, with the male catkins being more conspicuous. After pollination, the female catkins develop into seed capsules that disperse seeds in the wind.
Willow and Alder.
how am i supposed to know
Catkins are also called aments
hazel
Cats don't produce catkins. Catkins are slim, cylindral flower cluster with inconspicuous or no petals produced by some plants.