rejuvenation pruning of flowering shrubs.. involves taking one third of the plant down to a couple inches ... every year ...

take the time to take the tallest ones.. and you might be surprised how you lose a few feet real fast ...

new growth will sprout down low from the cuts.. and you will then..ibso presto.. have leaves lower down ...

if you cut them at 2 feet ... they will probably flop.. because of the new weight at height ... just making you more work .. you might be very surprised how fast new growth comes from down below.. with no insult to the massive root system ...

have faith.. it will turn out great ...

i did not watch any of these .. but this should give you a flavor of what need be done:

https://duckduckgo.com/?t=ffcm&q=rejuvenation+pruning+of+flowering+shrubs&iax=videos&ia=videos

ken

Just what I was going to say!

If you want to go down to 2.5' and basically start over, I'd wait until late winter and accept no flowers for a year or two. However, based on some of the other statements it seems like you are fighting this plant. It wants to be a large upright arching shrub where the blooming branches nearly arch back to the ground.

seeing some suggestion of a house behind.. i suspect this shrub serves a very specific function ... i dont know why you want it so short????

in 50 years.. i never bothered to remove spent blooms ... and i still wouldnt bother with that ... but if you need the exercise.. go for it.. sure wont hurt ...

ken