When a plant is in leaf or when it comes into leaf, it has or gets leaves on it.

The trees are in leaf early this year. 今年树木的叶子长得早。

The bushes are just coming into leaf. 灌木刚刚长出叶子。

The shrub is about ametre high when it is in leaf.

The oak tree was still in leaf well into winter.

The grass was green and the trees were bursting into leaf.

The trees were late coming into leaf that year because of the cold weather.

See also: leaf noun (PLANT)