60’s – 80’s creature feature of a giant worm/slug

This has been bugging me for years now…

From what I can recall:

It’s a creature feature from the 80’s but my memory makes me think it may be from as far back as the 60’s…

Film starts off with an elderly couple doing gardening in their home. The husband gets stung by a rose or /something/ on a rose.
Has serious pain/heart attack and gets rushed off to hospital where he eventually either turns into a giant worm/slug monster or one grow inside him, eventually splitting him open. Then ‘running’ amok in the hospital and possibly the town…

“FEELS” like The Blob but it’s not. I’m sure a flower of some sort was involved and no space ships…