They do this with some plant such as Nepeta (cat nip) sniff, eat and roll in/on it it gives them a high if smelt and may sedate them if eaten. My cat smalls flowers and chews some and not others. My Weigelas are all very mature and have never seen the cat go near them. This plant may suffer from the cats attention I would find somewhere to keep it ( better outside) till it can be planted. When you first plant it you might want a ring of pepper around it to keep the cats away.

How odd - as far as I know, this plant isn't particularly attractive to cats - Nepeta's the one they behave like this around.

My cat does it with Nepetas but he often can be seen smelling and rubbing other plants such as Jacob's ladder Penstemons and now I have one very flattened Heuchera that he lies on.

This is the first blooming season for my Weigela. I have 3 cats, one outside and two inside who come out with me when I garden. My indoor male is absolutely in love with my Weigela! He looks like a lovesick fool, all dreamy-eyed, face buried in it and rubbing himself all over the branches. My other two cats show no intrest in it other than lying near it. I was relieved it can't harm him.

How sweet I find they do like to smell plants and some appeal more than others.