It is probably dry at the root. The first thing a plant under stress does is drop its flower buds.
tropical tree with yellow white flowers
no it isn't kid
too much water
Stonecrop
Is Epsom salt good for Tibichina Tree with a lot of flowers but drooping leaves?
stonecrop
Stonecrop
Carotene gives yellow color to the leaves.
Sounds like a Berberis.
A very common crop that is noted for its many yellow flowers is mustard. Some farmers grow this and harvest the leaves while others harvest just the seeds.
Coronation gold yarrow has goldenrod yellow flowers with silvery leaves.
It could be a Senicio.