I have frequently attached a 4' trellis to the top of a fence as a line of sight sight screen. With a 4x8 you can increase the fence by 3 to 3.5' taller, and very economically cover 8'. A series of these could do your whole back fence. I attach them by predrilling to not crack trellis wood and using deck screws and electric screwdriver. A climbing hydrangea is slow growing at first. It gets quite woody, very large, and very heavy, like a Wisteria it might break a lighter to mid duty trellis. Honeysuckle 'Scentsation' or a smaller trumpet vine such as 'Indian Summer' may work better and survive in zone 5b (tbey are rated to 4). They drop their leaves, but might block quite well, except in winter. If this was my fence I'd pair Honeysuckle 'Scentsation' with Clematis 'Jackmanii' both have a long season and repeat blooming. That also gives you fragrance and hummingbird draw. The honeysuckle also has nice red berries late in the season for visual impact and the other birds. Both grow fast and together you should get enough vine growth to be a decent Winter block. Here's an internet photo of the in bloom appearance. The light colored honeysuckle really shows up in a twlight garden. And it does get woody too for that forest cottage look. I'm guessing this honeysuckle would cover about 20' linear. And one Clematis half of that? I've actually started this pair on my gazebo entrance.

Hi Dingo! Wow you must be my neighbor, thanks for the local insight!! We are in Hinsdale. Yes, I am aware of the alkalinity.. actually I am getting a neutral reading on my soil here, using one of those metal shaft ph things that look like a meat thermometer. 7.0. so, my plan was that since the roses also prefer a slightly acidic soil, that I would add Aluminum Sulfate to the soil to try to get it between 6.0-6.5, for the roses to be happy and also for the hydrangeas to grow more blue. I already bought about 5 endless summer hydrangeas (3 of the original, 2 Bloomstruck). with the idea that the original ones would be in the middle as they can grow about a foot higher than the 2 others. The bloom struck may look a little more purple and could go on either side of the originals. I think the slight height difference and adding some of that purple to either end of the row of blue may look nice.. but we will see. I hadn't heard of the Nantucket blue but that sounds like exactly what I'm looking for since I got on this hydrangea kick after visiting Nantucket this past summer! All of the homes with their blue hydrangeas was just stunning!! Thanks for the tip, I will go to Meinke's!! Maybe I'll get lucky and come home with roses for the front this season after all! Yes, I thought about clematis. that is an option, but I so have my heart set on this cottage look with the old English looking garden roses and hydrangeas. It's going to be a challenge but worth it if I figure this out.

@luis_pr you wrote: "Other species of hydrangea grow shallow, tiny, fibrous roots mostly around the top 4" only so I doubt they will push up the pavers much unless the pavers were already loose. They also need frequent watering and am not sure they will get enough water.Probably enough at first but not long term... as they start to grow under the pavers, they will not get enough moisture. The roots will then be dried out by the pavers during the day. Then at night, the pavers will release heat, just as the hydrangea roots expect some cooling. Not necessarily good conditions for the mopheads." Your prediction of what happens when they start growing under pavers and not get enough water - is interesting and sounds logical. I wonder if this is why I have trouble with some jasmins I have planted along these same pavers. Their opening is also 18"x8". I lost one last year after it lived 3 yrs and now I'm losing another one. It looks like it is dying from thirst even though It's getting drip irrigation water every day. Could the cause be the scenario you describe? There are still 4 other jasmins planted the same way (in little openings in pavers) that seem to be doing well.

The problem with delphiniums in my area is the wind blows them over. And not sure I want to grow things I have to stake... Do you all stake yours? I have to be careful to plant things that don't mind wind. Maybe delphiniums are worth it tho.. Frances thanks for the ideas. I am definitely going to start some Dames Violets. Its funny... we were in Alaska last summer too! Didnt get to Fairbanks tho. I was amazed how stuff grew tall even in such a low zone! I wonder if hrs of daylight has to do with it?