Are you sure the oakleaf hydrangea will survive in Milwaukee? They occur naturally in an arc from southwest Georgia and the Florida Panhandle to Memphis. Most of that is zone 7a, 7b, 8a.

Oh you bet they will...need a micro-climate for best performance. There is a bank 15min north of me that has a couple huge oakleafs. Down the road a nursery has several mature oakleafs.

Yes you may sacrifice flower buds in some years.

I'm technically a suburb of Milwaukee, so Milwaukee itself near closer to the lake would be even better with zone 5b

'Little Honey' is not nearly as robust as the larger, straight green forms of H. quercifolia, so site accordingly :-) It can also scorch if exposed to hot summer sun in the afternoon, so I'd provide at least partial shade.

I pair mine with plants that have a burgundy or purplish hue - purple leaved forms of wood spurge, Euphorbia amygdaloides or xmartinii, a purple leaved daphne (D. houtteana), heucheras and an iris hybrid that forms maroon flower buds that open to yellow. And Japanese forest grass, Hakonechloa macra 'Aureola'. I like the contrast of the gold foliage against the purple and the fall color of the hydrangea picks up those same burgundy tones (as does the grass). Not all of these will be hardy for you in zone 5 but you get the idea and I'm sure you can find some zonal appropriate alternatives.

I was just thinking a blue grey hosta would look pretty cool.

I might be able to get it in a #2 cnt. from a local source so that may help with the establishment.

I would recommend some high afternoon shade. They grow slow so have patience. I've had mine for 4 years and it's about 28 inches tall and started out as rooted cutting. Fall foliage colors are rather spectacular with the yellows and reds.

As mentioned above it will only get east and southeast sun.

Couple of you mention tough to establish and not as robust.

Do you just have to situate it appropriatly and be patient...or is it less hardy than the others?

Can't comment on hardiness since I'm in 6b, but I wouldn't attempt to plant it in a spot where drainage could be even just slightly questionable. Which I did and killed one of them. Raised bed is a must, IMO.
Another 'dead body' resulted from the late season (September) planting.
And the third one being planted in ground in spring all of a sudden in a middle of the season began declining for no apparent reason and had to be moved back in a pot where it almost recovered before winter.
So, my score is: 4 attempts= 1.5 alive + 2.5 dead.

Hardiness is probably not the issue but vigor could be :-) I would attempt to locate the largest specimens you can as IME, the younger or smaller the plant, the less likely it is to 'take' or establish. This was borne out at a wholesale grower I worked for that lost an entire planting of LH plugs for no apparent reason - they just dwindled away. I grew my 1G plant on in a container until it reached what I considered to be a plantable size. It is now about 3'x3' and very happy.

I was going to mention the issue Gardengal brought up - many growers have given up trying to grow this wimpy plant, but apparently some are having some success as there are a number of mail order outfits peddling the plant. I bought mine at Yew Dell Gardens near Louisville KY, but I don't know the real source. Larger the better as she recommends.

'Little Honey' is an introduction from Briggs Nursery here in WA state, discovered as a sport of 'PeeWee'. Unlike most other oakleaf hydrangeas, it is propagated by tissue culture, which may account for reduced vigor. And "off-color" plant often do not grow with same robustness as their all green counterparts :-) But as long as you can provide proper cultural conditions and obtain a decent sized plant to begin with, it should do well.