Personally, I think odd number plant groupings look best - so do 3 or 5 bushes. I just planted Annabelles at 3ft spacing hoping they will support each other. Good luck!

Mine are all 5ft wide. I chunk out hunks each March and have sprinkled them around my 2.5 acres. Three will be plenty in that space.

You have then too close to the house. Move them out at least a foot or a foot and a half. You don't want the plants to touch the house as they grow. Mine are mature and most of them I have foot between the house and the plant.

I have a fully matured Annabelle and it is huge! I would definitely go with 5ft spacing and plant further away from the house. I just went out to look at it. It is def 6 ft wide. Mine only droops after a significant rainstorm.

If you plant them where they are set (I’m talking about distance from the house), they will droop for certain because they can only grow OUT away from the house. If the Annabelles are expected to be 6 feet wide at maturity, the bed should be 7 feet wide (measured from the house out to the yard). It looks like 3 will be plenty.

I would plant 3..I agree with everyone that you should plant them further away from the house..they'll get better light and rain and it's easier to maintain the house and the plants when you leave a "service alley"..to keep my Annabelles pretty I do need to clip dead and bent stems and it's so much better to have space to reach them..it's hard to tell from this pic but I can reach these from all sides..I think these were planted about 2 ft? apart..I wanted a hedge..

Concur with 3 planted further out. Also, your fiancee is a wonderfully good sport. Congrats!

My Annabelle is at least 15 years old and is only restrained in width by a building, a house, a sidewalk, and a huge rhododendron. I have to get in there every year or two and dig out big chunks or it would fill the entire 10’ space available. This is a suckering shrub that will take as much space as is available given time. I would give it the wider spacing and if needed give it some support until the plants spread enough to join together.

When planting anything near a house always leave plenty of room for getting in and doing maintenance of the exterior.

Such as washing windows, if nothing else.

This includes leaving space for ladders every time somebody has to get up on the roof.

Also notice how tall your hydrangeas already are in relation to the windows. Planning for any kind of woody plant getting a lot bigger than it is when first purchased and planted is always a good idea.

Regarding the odd vs even numbers within each grouping there are various situations where an even number will produce the most visually successful arrangement. And odd numbers can tend to produce rigidity, triangles for instance are a "locked" looking (highly geometric) shape.

The height of Annabelle is fine in this case based on my experience. Mine gets to between 4 and 4 1/2 feet, no taller, and they have been that same height without pruning for well over 10 years.

I do agree with everyone who wants them far enough from the building. I would put the center of the plant at least 4’ from the house, and a bit more wouldn’t hurt.

I have Annabelle hydrangea and love them, they get a good prune back in winter. Your planting needs a bit more apart and brought more to the middle. They grow quite big. I like the buxus hedging in front, keeps them tidy. Also I plant lots of bulbs amongst them, looks great in spring as the hydrangeas start to leaf up after their pruning