I don't like fertilizing anything that dies back in my yard after Labor day here in NC. Additional fertilizer after that point is going to try and stimulate new top growth and what I want my clematis to be doing is saving energy for winter and not growing like gangbusters. Sometimes the clematis still grow fairly rapidly after that point since the temps have cooled off and their is more rain. At least I know that Mother Nature is coaxing them to grow and it is not due to my intervention. As for water, you can continue giving them that if the weather is especially dry in your area. Poke around in the ground and see how the soil moisture is in the vicinity and let that be your guide. I have stopped providing my clematis in the ground any additional water since we have begun getting sufficient rain and the temps have significantly dropped. Make sure your liquid fertilizer is not one high in nitrogen or you will stimulate a lot of vegetative growth and few flowers.

Establishment could be the tricky part :-) Generally, tree roots do not play well with hydrangeas (and a lot of other plants, for that matter). Mounding the soil for a decent planting area is a good idea but eventually the tree roots will work their way in. Watering will need to be attended to carefully as the roots will grab the lion's share of any soil moisture. You may have to fertilize on a more regular basis as well, as the roots will also claim the soil nutrients. Enziandom is one of my favorites, with incredibly large and deep blue flowers. I'd give it every care you can, including winter protection, to assure reliable blooming.

Thanks (everyone) for the feedback- very helpful. Some additional details below: So, Math was never my favorite subject. I went out back and measured the distance of the fence from corner to gate (which is where the privacy is really needed). We're at 28 feet total. To get to the young maple (which is a natural transition point) it's 20 feet. So, we're looking at the hedge being somewhere between 20-28 feet depending on how we want to taper/transition. The Boxwoods are about 1.5' wide. I'm thinking we will space them about 10" apart...that should give us coverage along the fence with a little wiggle room. It will add a bunch of immediate privacy and some room for the hedge to establish and then connect...and it sounds like a season or two should do the trick. Once we transplant the current grasses/plants and remove some pavers, we should have a width of about 6 feet to work with, reduced to about 4.5 feet at the Hydrangeas. Hoping this is enough space for the hedge and to texture some plants in front. Specific to the responses above: Steve- good thoughts on spacing and thanks for the Geranium and Hosta suggestions. We have a lot of Hosta in our front and sprinkled through the back. We will definitely use that to complement the boxwood hedge. The raised bed idea was two-fold: improve drainage for the hedge and make sure they don't compete/hurt the Hydrangeas. I was thinking a base of peastone/gravel before backfilling the bed would solve both problems (but making sure the depth of the backfill matched the current depth of the boxwood pots). We'll religiously trim the boxwoods as the current height works for us (another foot would be OK too). Beyond that, I'd need a ladder to trim and would like to avoid it...realize this may be a pipe dream after a few years, even with regular trimming? Digger- the Boxwoods are Common/European (Buxus Sempervirens). Based on the feedback here, I will space them a bit and get closer to your 18" on center suggestion. We brought the Boxwoods home last Sunday. Haven't watered them yet since we've had ample rain. It doesn't sound like watering the pots will be neccessary unless we hit a dry spell...and that seems unlikely with the New England spring forecast. I'll keep checking the root balls...I was going to build the raised bed using pressure treated 4x4 for the posts (sunk in ground). 2x4 treated cedar for the side boards. I was planning on building the box without digging down and sinking any of the cedar. We're on a light slope so I'd build the top of the box first, elevate it and level using wood blocks, then skill saw tapered pieces to ground level to run with the grade. Remove the blocks once secured. Add some aluminum spanners throughout to prevent bowing and backfill the bad boy. Final depth would be slightly above the depth of the pots in order to put drainage stone on the bottom and backfill with dirt. We run soaker hoses throughout the garden to handle watering...as far as the boxwoods themselves, we looked at nurseries, but couldn't find anything in the 6' range for under $400/piece. We found the current ones at Home Depot for $99. Still cost us a fair amount, but seemed reasonable for an instant 6-7" privacy hedge. The boxwoods themselves came from a nursery in CT. I suspect you could contact your local HD and make a request for however many you want...that's what we did (Waltham store). Thanks for the VT boxwood link too! Oracle- I didn't even consider the sunlight factor or wider bottom versus top. More reason to space them further apart. As I mentioned above, we're more like 20-28 feet in needed privacy, so the 10 boxwoods should balance better. We can certainly return some if all 10 aren't needed. Thoughts on a distance from the fence? We have 6 feet to work with for most of the hedge row, but we'd like to add some plants/shrubs in front to layer the garden. The Hydrangeas are 4.5 feet from the fence to center and we don't want to touch those...so we're tighter on space for about 8 feet of the boxwoods that will sit behind the hydrangeas. Do you think the boxwoods will hurt the well established hydrangeas given our space constraints? The berm idea is also interesting. I like the idea of less work, particularly if it provides a healthier environment. No standing water in the garden area. We're not bothered by the Boxwood smell, aside from the 'cat pee' driving our dogs wild. They'll be thrilled. Can't wait to chase them out of the gardens on a regular basis this summer... Based on the feedback so far, maybe the raised bed is overkill. Yes, it would look nice but it will take some time/money to build and there is a benefit to getting these in the ground sooner. How about Oracle's berm idea? It would add some texture to the garden and presumably help with drainage too. More than anything, I want to make sure we don't hurt the Hydrangeas. It would be a real bummer if the boxwood row doesn't take well, but I'd much prefer that over having the boxwoods thrive at the expense of the hydrangeas. Attached is a picture that gives a sense as to the current spacing between the fence and hydrangeas...you can see the fence line at the bottom left corner. Thanks again for all the suggestions. Would welcome any additional thoughts.

Plant in the existing soil, between large roots, and use mulch to encourage establishment and growth. Do not pile mulch against the base of the fence or place anything else against it, that might cause the wood to be kept moist. (Also if the bottom cross pieces are resting on the soil the dirt should be dug out beneath them so they do not rot. The depth need only be enough to eliminate soil contact). Fruit should be out in the open, where it gets full light. Persimmons are hot summer climate trees, not a regular feature of British plantings. In addition to the R.H.S. web site and magazine you can get ideas for plants, read discussions of methodology in magazines that are on display at libraries and book stores - I see ones like B.B.C. Gardener's World and English Gardening over here. It seems a source in the U.K. itself might have multiple additional titles available. And as I believe was suggested previously visits to any nearby private or public gardens could be quite instructive. Public ones in particular might even have classes, guest speakers or other events of interest. If you are saying you want the plants to be hardy to the equivalent of 5 degrees F. then that is comparatively mild by continental U.S. standards, except in parts of the southern and Pacific Coastal areas. You can see here where you fit in relation to U.S. winter climates, with the coldest British USDA zoning being 7 whereas large sections of the U.S. fall well below that: http://www.trebrown.com/hrdzone.html Note - as it says in the discussion at the page linked to - that the minimum temperatures associated with each Zone are average temperatures and not the coldest it gets in each Zone.