Some before and after pics of the area.

From the opposite end before I cleaned out the vines, leveled the ground and placed pea gravel.

I'm going to install a flagstone path here with pea gravel just like in my back yard.

back yard heading to side yard.

Last pic...

Oakleaf hydrangeas are native to the southeastern U.S. (Florida, Georgia, Mississippi and thereabouts) so I would try oakleafs first. As for how wide they get in Florida, hard to say unless someone from there who has them chimes in. The US National Arboretum sent test plants throughout the region so I can only hope that they got size estimates from FL and that these were taken into account when the estimates were made. But, alas, they are estimates. If you are very concerned, add 1/2 foot to 1 foot extra to the dimensions. Since they are very new introductions, I doubt a lot of people have had them for 10 years or more; that is usually what the size estimates are for. By adding 0.5-1 more foot in between the plants, you may be covered and if they still get too big, you can always prune them.

So for a 4.5' estimated width, assume a size between 5' and 5.5' in Florida and separate the main trunk of every pair by 5', 5.5' or even 6' if you want.

I am not sure if I would use pea gravel with hydrangeas. I usually go for organic mulch like hardwood mulch, pine needles or pine bark mulch. Not sure if the gravel will absorb heat and dissipate it as well as the others. And the others absorb and retain water better. Good news is gravel tends to be acidic so the hydrangeas will definitely not complain about that.

Referring to pics 1-2, between the a/c units and the wood fence to their left, I would leave that path/area open so people who maintain the a/c units can come/go/do their work.

Invest in a soil test while you are working on the yard so you know how the soil where the roots are going into will be like. Consider that you may have to water a lot, usually about 1.5 gallon per watering per plant if the soil is sandy.

Thanks Luis. I wasn't clear in my earlier posts. The pea gravel was a somewhat failed attempt at xeroscaping my north facing somewhat shady side yard. It was in reaction to overgrown jasmine that had invaded from my neighbor's yard. That "before" picture was after I had already trimmed several feet of it away. When I bought the house the vines had actually grown into the AC units! You couldn't even walk back there.

So I ripped it all out and xeroscaped. It looks much cleaner, but also looks sterile. The stones are also hard to walk on and it's very difficult to get my lawn mower back there. So, we're redoing it again. This time we're going to rake back the pea gravel, lay a flag stone path around the side, then put pea gravel in between the stones. I have a new project elsewhere for the extra leftover pea gravel. It's much easier to walk on the path in the backyard with the flagstones in place.

Then while we're doing this I'm going to put in a raised bed planter on the right side of picture one, about 4 or 5 feet wide. I'm definitely leaving planty of room to access the heat pumps. I'm going to raise this bed up at least 6" and fill it with locally made potting soil. The perimeter of the raised bed will be made with matching flagstones so it will look something like this picture from the web (not my house and I didn't take this picture). I wasn't planning on using pea gravel for the "mulch". It gets so hot here it would literally cook the roots.

I tend to like pine straw for my mulch. Not as long lived as pine bark, but I like the look and I have been told that it doesn't attract termites. It's also easy to remove when it breaks down and replace with new. Acidifies the soil too which is important here, because my stucco concrete block house releases alkaline material into the dirt. I need to do this twice a year, but it's cost prohibitive, so I only do it once a year. It takes over 300 bales to do my yard!

I'm worried that they may not get enough light in this location. Does anyone have any opinions on this?

Can I really get by with just 3 Munchkins for 17' of bed? My wallet will thank me if this is so.

How many years will it take for them to fill in this space?

Thanks again everyone!

My hydrangea leaves suffer from sunscorch if I let them get sunlight from dawn thru sometime after 12pm ish so plan on giving them dappled sun or 2-4 hours of sun. Even bright shade works fine. They should reach the advertised dimensions in about 10 years. Of course, they may tweak those estimates once real people attain 10 years and say yay or nay! Ha!

Luis are you talking about your oakleafs or macs, or pee gees, etc?

We LOVE all types of hydrangeas. But, unfortunately most of our yard isn't mac friendly... I put in a bed a few months ago. Too many plants in too small a space, but I don't mind. I'll post a few pics. Hijacking my own thread... ha

The bed is on the south side of my yard facing east. Gets fried every day in the FL sun. The Lime Lights do just fine. Unfazed. The Penny Macs get droopy. The ES and Blushing Bridge look down right sick. But, I have them on an automatic drip irrigation timer and they get watered at 3pm when the sun starts to go behind some tall trees. They perk up by 5pm.

I have 6 Incrediballs waiting on my at my nursery (they special ordered them for me).

And, I'm going to plant 3 or 4 Munchkins, one Harmony and one Snowflake. I can't wait for my order to come in.

Oh, yeah, you mentioned that it could take ten years for my oakleafs to fill in that 17' bed. I'm patient enough to wait two or three years, but not ten. If that's the case maybe I should plant 5 or 6 and then trim back in a decade.... what do you think?

This is the before pic for that area. I had 20' tall Ligustrum, leftover from the previous homeowner. I thought I was planting in a shady area. Turns out when you rip everything out it dramatically changes the light...

The mac's are the most sensitive ones to sun here but over here the oakleafs can suffer if not planted in a place that gives afternoon shade. I cannot comment on the arborescens as they are in bright shade, not sun. From postings here, the appear to be slightly better in sun than macs but not by a lot. The panics and oakleafs are at the top of the heap. However, oakleafs HAVE TO HAVE well draining soil. I had an Alice that died on me when Texas had an incredible amount of rain for four months due to El Nin~o.

Thanks Luis. And, thanks for responding to my question over on the camellia forum.

I ended up ordering 5 Munchkins from hydrangea dot com. We'll so how it goes. I'll post pictures (much later...)

Thanks again.