Anything you plant will have to be able to grow in the existing soil conditions because if you actually bother to dig sideways under your asphalt you will undermine it.

Climbing hydrangeas need a wide and fairly rough surface for the aerial rootlets to attach to - a tree trunk, fence, side of a building, brick or stone chimney. They do not work well on any sort of trellising or arbor. They also get to be massive and eventually, very heavy. Probably not the best choice for that application.

But as long as the openings have just a soil base (not a solid planter type thing), then you can plant in them. But I would be concerned about the roots receiving adequate water.

Knowing where you are and having a pic of your specific situation would help with suggestions.

tj

Lots of additional talk about using this plant here:

Climbing hydrangea - GardenWeb - Home Design Discussions

Zone 7a (I’ve grown it successfully here so that’s not an issue). I’ve included a picture of my garage. It’s v similar to what I posted. Thank you!

Sorry here’s my garage.

You need to pick another vine. A climbing hydrangea will not do well in that situation. Are there even any planting areas there?

Gardengal48: Your point on watering is a very good one. I can rig something with the drip irrigation from the neighboring beds to the two external planters but your point may mean no central planter. I was able to successfully grow CH up an arbor so I think the trellis may work till it goes lateral and out (see picture from old house. Apologies for the quality but it was in an album on phone and I couldn’t figure out how to upload from library so I just took a picture of the photo. It was covering the top of the arbor when we moved and obviously would have to be pruned quite a bit). I’ve seen CH on the side of houses and shed but know it can damage siding, hence the idea of a lattice that would prevent direct contact.

Hi Gardengal: any suggestions for alternatives? Can’t do climbing roses or anything that is part of the deer buffet!

Provided you have an adequate planting area and receive enough sun, I'd consider clematis or honeysuckle.

fyi: honeysuckle is a deer magnet here. Don't know about clematis and deer though.

Deer have different appetites depending on where one is located :-) They will munch the flowers off of hydrangeas and clematis here but leave the stems/vines alone. If you have deer, assume that nothing is fully deer proof and invest in a good repellent spray!!

Yes sadly honeysuckle and clematis will not survive the deer here (except sweet autumn clematis which they ignore). I think it’s close to being declared invasive here so will stay away from that. Also looking for something with more structure when leaves are gone. Will do some more research. I may have to brave wisteria if I can figure out support structure. They ignore it here.... or I should be satisfied with summer vines like Mandevilla. Thanks so much for all the comments and thoughts.

The species of deer matters. And deer resistance lists almost never indicate which species was being observed.

Hydrangeas repeatedly appear on deer resistance lists. Currently I have a mule deer eating the new growth off of a bigleaf hydrangea during its at least twice daily visits. A friend with property in the same county - and also frequented by mule deer - says bigleaf hydrangeas are impossible there. But they don't spoil the hairy leaved kinds such as aspera.

I have two climbing species of honeysuckle growing natively here on my property. They are currently making their new spring shoots, I have yet to see damage.

A friend that used to garden in the country says they would not do that again without a deer fence. The urban neighborhood where they are now has no deer.

One issue with the climbing hydrangeas is that they can take up to 10 years to blossom! Are you willing to wait that long? Some will bloom sooner - maybe 6 -8 years but the are VERY slow to get happy. I have one that took almost 11 years to the first bloom. Mine are all in the back with other blooming plants in front of them so it did not matter too much. Some are along a 5 foot chain link fence while several others are growing up some Douglas Firs. The ones on the trees are yet to bloom but we are hopeful that this will be the year to bloom.

@Rosa M, I'm also in 7A... I would suggest a combination of Morning Glories and Moonvine; you can put them in a container (1 gallon per root) and they'll grow up the trellis just fine. They're deer resistant, but if deer become an issue then you can spray the lower leaves with something like Repels All. I grow super hot peppers, too, and prefer to take one of the "bad" ones, blend it with water and a drop of dish soap, then spray plants with that to repel pests.

I'm pretty sure that it would be OK to add a few Forget Me Nots or verbena to the pot to cover the soil. That's what I'm doing right now; I have a 5 gallon container, so I have 2 Morning Glories, 2 Moonvines, and 3 Moss Verbena, but I'm prepared to take out the verbena if the vines don't do well.

Jason: thanks for the suggestions. I’m going to try a combo. Sps wash: yes CH is an exercise in patience. The 7 gallon sizes I got are blooming so I think I lucked out. My previous ones took a while to bloom. But I do like the leaves.