Hi there.

I was looking at your photo, noticed everything does a great job of 'pointing' to that central area. HOWEVER, did you notice that larger shrub, which is blooming right now in the picture, well it's taking the viewer's eye away from the center. Maybe you could transplant that shrub, first.

As far as what to plant there, Let me think . . . . .
It would be nice to plant something with a large leaf, that might keep your attention because everything else seems to have a smaller leaf. Maybe a large-leaf hosta would be nice there.

I could see a hydrangea there instead.

You could use the center area as if it were a planter - and create an arrangement of plants, with a nice tall something in the middle then circular plantings around that. Personally I would have a ball with changing annuals year after year - but there are plenty of perennials you can use there instead, depending on what colors you use around your home.

what i would do and this is just my opinion. I would do the outer edge in purple or dark blue lobelia and then a inner area in snow in summer or some other white ground cover and then that center pot i would put things that vine along with flowers with some eyepopping color. I think that would also tie the bush in that is a georgous bush i dont think i would move it or take it out. If this is a summer picture and I am assuming it is not because whatever is over that trellis the flowers are not blooming. If it is a summer picture that area really needs lots of color. Something else you could do is take that flower pot out of the center move it elsewhere like on the deck at the start of the picture and put a nice water feature there, that area really needs a nice focal point in my opinion. That is a great area. If this is a spring shot and i think it is a recently taken picture you need more color in that area that blooms early spring, I would get things that bloom early spring and last through fall if it was me. And consider winter interest also. I love the way that trellis and the bushes draws you further back and peeks your interest into exploring further. Really a nice thought out area, and alot of work went into that. You can really tell it is a labor of love.