Deciduous trees shed their leaves (or defoliate) in the fall. What happens in the spring?
I'm looking for words like bloom/blossom, but these refer to flowers, right? Are there similar verb/noun referring to leaves?
Leaf out -- [for a plant] to open its leaf buds.
Most of the bushes leaf out in mid-April. The trees leafed out early this year.
Leaf out -- (intransitive, of a plant) To open its buds.
Example of usage:
If it seems like some of your favorite trees and shrubs have been slow to leaf-out or flower this spring, you are right. (Michigan State Uni)
There's the related expression bud out, but I'm unsure whether it has the precise meaning of "leaves sprouting out of their buds" or it's meaning is "buds appearing on branches". Maybe there's some wiggle-room in its usage. An example of usage:
In early April, soon after the leaves bud out, clusters of snowy, 1-inch, white or pink flowers cover each slender branch of this densely foliated shrub. (Google Books)
An oldish (1817) example of bud out indicating the appearance of leaves:
The verdant leaves bud out when you appear,
And all the trees their brightest liveries wear;
Another example (1987):
The leaves are covered with a matted, wooly pubescence. They begin to bud out early in the Great Basin, frequently in February [...]
From a novel titled Hacienda (1997) - here it's clear that it's the leaves that appear from the buds, not the buds on the branches:
The trees and brush were just beginning to bud out, the delicate leaves barely hinting their future color.