Should I cut it back?? Monster butterfly bush

[GrimApatheia]

Hi all
Just purchased a HUGE butterfly bush at the local greenhouse, it’s gotta be at least 4’+ tall. It is getting later in the season and I’m wondering, when fall really sets in, should I cut it back?? If so, how far? It seems almost sacrilegious to cut such a plant back, but I want to make sure it stays healthy and huge for as long as I can keep it. Thanks!

 

[DirtMechanic]

I prune mine when it goes dormant. They can get big but grow pretty fast so I prune for shape and habit first and height second.

 

[Oliver Buckle]

They can easily make twice that size given good conditions. It looks a bit droopy, like it needs a good drink maybe.
Like DirtMechanic I prune for shape, but I have known people take established plants down to near ground level.
They produce huge numbers of wind blown seeds that will lodge anywhere and start growing in places like gutters or badly pointed brickwork. These cost people like railway companies millions to get rid of, so it is sociable to dead head them as soon as the flowers go over. You also get more flowers of course.
When you prune you could try striking some cuttings, they take relatively easily.

 

[GrimApatheia]

They can easily make twice that size given good conditions. It looks a bit droopy, like it needs a good drink maybe.
Like DirtMechanic I prune for shape, but I have known people take established plants down to near ground level.
They produce huge numbers of wind blown seeds that will lodge anywhere and start growing in places like gutters or badly pointed brickwork. These cost people like railway companies millions to get rid of, so it is sociable to dead head them as soon as the flowers go over. You also get more flowers of course.
When you prune you could try striking some cuttings, they take relatively easily.

Perfect. And yeah, it had just been repotted from something like a 3gal pot! Thank y’all for the input !!

 

[GrimApatheia]

They can easily make twice that size given good conditions. It looks a bit droopy, like it needs a good drink maybe.
Like DirtMechanic I prune for shape, but I have known people take established plants down to near ground level.
They produce huge numbers of wind blown seeds that will lodge anywhere and start growing in places like gutters or badly pointed brickwork. These cost people like railway companies millions to get rid of, so it is sociable to dead head them as soon as the flowers go over. You also get more flowers of course.
When you prune you could try striking some cuttings, they take relatively easily.

Btw, how far back should I cut it? Like, how many inches should the stem be left?

 

[DirtMechanic]

Btw, how far back should I cut it? Like, how many inches should the stem be left?

Well fertilized- prune hard and it stay smallish. Like me, fertilize little and don't prune as much and its taller than I am but out in the middle of the yard unlike yours.