A hedge, more or less, is a wall. One thing I think always looks odd is a solid privacy fence (a wall) with a hedge (another wall, but green) in front of it. I think it's better to extend the height of the fence without blocking the fence entirely. One way to do that is to place large tree forms (of the height you wish to grow) in front of the fence. They can be placed as singles on periodic spacing ... or as groups, depending on what you are trying to achieve. They can be spaced so as to connect completely at the canopy area, or be spaced out so as to allow gaps, again, depending on what you are trying to achieve. Crape myrtles are one plant that can be used in this way, but there are innumerable others, depending on what you are trying to achieve. See sketch. (Oddly, this sketch I did awhile back was for someone else in Austin.) To question whether vines can achieve the height you want in a single season indicates that you have no experience with annual vines. Morning glories can grow 25' ht. in a single season if you do the things (common garden practices) that make them happy. Perennial vines are usually slower to get going, but they are there continuously. The easiest vine trellis is made by erecting two poles a few few apart. Install a large hook at the top of each one and span a chain between the poles (hung on the hooks.) Tie twine to the chain at intervals and connect it to the ground (tie to bamboo barbecue skewers from the grocery store.) Annual vines will quickly run up the twine and coagulate around the upper portions. (It can form a solid screen if you drop enough twines.) As annual vines go, there is nothing faster than gourd. Once it begins to climb it will reach the top in a week and begin sprawling all over the place in a couple more. (With kids around it can be a treat to watch the gourds form. Especially, try maranka -- the caveman club gourd -- for something they will really enjoy.) But leaves begin dying off from the bottom up after not too long, so it would best be followed with another annual vine ... like morning glories (Heavenly Blue cannot be beat) or Moonflower vine, if scent and evening flowering appeals. (IMO, moonflower makes the better screen.) I don't think it would be practical to trellis in your whole back yard. You might use the tree form shrubs for most of it, and use a trellis where you need the quickest screen.

they are conifers.. there is a conifer forum.. if you are interested .... i dont care otherwise .... you are probably thinking about green giants ... shade restricts growth rates ... and on a lot of these.. you have to remove all but one leader.. so but them smaller ... smaller plants get established faster.. and grow faster than large transplants .. a 2 foot GG will outgrow a 5 foot transplant.. in 5 years ... mail order them.. if you cant find a local source ... ken

Your probably bang on with the cedars however they will take a long time to fill in an area. They don't require a lot of work compared to a vine generally speaking. I certainly don't recommend vines to fill your need because the privacy they give would generally be subject to the season. Below are some comments on the ones I have experience with. Most of the summer one of my chain link fences gets covered in Clematis Tangutica. I think it was called Clematis Bill MacKenzie. Its an amazing mess of yellow flowers. The nice thing with Bill MacKenzie was how fast it fills in during the spring over my other vines. I do have other clematis but nothing as bushy and filling as Bill MacKenzie. You could also look at Virginia Creeper but be careful as it can get out of control very fast. The neighbor behind our house has his crawling over his back fence snaking through the back lane and strangling parts of my garden. If you don't mind planting annuals every year you could try morning glories depending on the size / height of the area you want to cover. I've had good experience with morning glories all over my limited space. I'd seriously consider a long term investment though like cedars or some other type of bush. Evergreens for your area will give you all season privacy. Or if winter privacy isn't a big deal consider an edible bush like saskatoons. Well my 2 cents.

We have a similar situation; a medium sized suburban yard with a mish mash of chain link fence. Replacing it with a privacy fence would be very difficult because a long stretch of it goes right through the middle of 40+ year old thicket of honeysuckle bushes with massive trunks and roots. They are great for privacy in the summer, but do almost nothing all winter. Neighbor has three motion lights that shine right in our windows much of the year! On one section with no honeysuckles we got the rolls of 6' reed fencing and tied it the 4' chain link with wires. It held up well for a few years but the wind and animals trying to climb it damaged it a lot. The wire holding it together is thin and starts to rust and break after a few years too. Cutting it back to 4' when it got ratty helped tidy it up a bit, but obviously a lot less privacy. It is a very temporary solution at best. Since your fence is not even on the property line, I concur that getting a new and more private fence pushed back to the line is a better solution. If that doesn't pan out though... the reed fencing is an option. Ideally you would pair the reed fencing with some type of evergreen shrubbery which will help as well. They help with noise too. We have a massive silver maple and previously had several in our yard and next door. Yews would grow under them, slowly at least. Sweet woodruff is a good groundcover for dry shade too, although it is not evergreen. If you do put in any shrubs, plant them far enough away from the fence so they have room to grow. I have seen our one neighbor out with a scissors cutting off just the very tips of our red-twig dogwoods that stick through the fence. People are strange.