Looks like Rhamnus frangula 'Fine Line'

whatever it is.. is improperly sited.. im not buying your impression its slow groing.. the 3rd pic shows rather healthy leader growth ... lets see if we can figure this out

heres the data sheet.. i have to run .. note zone info ...

https://www.provenwinners.com/plants/rhamnus/fine-line-buckthorn-rhamnus-frangula

i suspect by the end of next season.. its not going to fit in that space .. so heavy pruning will begin.. and sooner or later.. that will destroy the plant.. unless the owner learns how to do it right ...

ken

You can probably ignore the previous comment :-) That IS Rhamnus 'Fine Line' and it will stay quite narrowly columnar. It may need some slight trimming periodically but will nicely fill that area without overpowering it. It rarely exceeds 24 inches in width.

Thanks everyone - yes Fine Line is exactly what it is. I actually asked owner and he has the proven winners tag. Says 5-7’ tall and 2-3’ wide. This will perfectly in my desired space (more space than in this pic)

I’ll pass along the advice given here to him. Thanks all!

Fine Line will exceed 5-7' tall and 2-3' wide. Also, even though its seeds have low viability it's still considered invasive in some areas. See this link: Woody Invasives of the Great Lakes , and see comments under "low fruiting or sterile varieties"

Hmm. I've been spec'ing this shrub since soon after its introduction and in the intervening 15 or so years, I have never had one exceed 30" in width and 6 feet in height. And this is the land where everything grows king size! I'd be very surprised to see one exceed the stated dimensions.

I've seen older plants that are greater than PW's specs. In fact there's a reviewer from NY right on the PW Fine Line webpage that stated that their plant after 8 years in the ground was about 10' tall and narrow at the base but about 5' diameter near the top.

Just break out the secateurs from time to time.

FINE LINE is a registered trademark used to sell 'Ron Williams'. With only 'Ron Williams' being a cultivar name. As with Thuja occidentalis 'Smaragd' the degree of narrowness varies somewhat from one planting to the next. With an example of a broader shape being shown here:

Rhamnus frangia 'Ron Williams'' aka 'Fine Line' | Plant & Flower Stock Photography: GardenPhotos.com