forsythia bush

Question

We had a hard winter – the plant has no green leaves, just a few buds that won’t bloom. It’s a 1 year old plant and it gets full sun.

Answer 1

In these situations, patience is the best policy. It may still put out leaves eventually, so don't give up on it yet. You can also prune it at the usual time to encourage new growth:
https://www.gardeningknowhow.com/ornamental/shrubs/forsythia/forsythia-pruning.htm