Some other factors to consider when thinking about hedges would include how much or little water you want to provide, whether it also has to be deer resistant, whether you are dealing with full sun or shade, and are you high enough up in Kensington that you need to worry about freeze tolerance? It can be significantly colder at the highest parts of Kensington that it isn't quite a Sunset zone 16 in a bad winter, with lows down to 20F a real possibility. I work on lots of gardens in the Berkeley/Oakland/Kensington hills areas, and it may be most useful to see what is working well in your neighborhood, and what appeals to you. You may also need to factor in that neighbors may get riled up if you block their distant views, just as you would if someone blocked your views. It may pay to take a more measured approach to creating privacy without planting a future monster. Personally I find many reasons to consider using clumping bamboos for hedging purposes; with the main reason being they don't need pruning to control size if you select the appropriate species for the height desired, they tend to stay narrow yet can grow tall, and pruning is easier when it simply involved removing old culms rather than ladders and pole saws. On the other hand, most bamboo species prefer a good amount of summer irrigation and are constantly shedding leaves and culm sheaths. The Sunset Western Garden Book Encyclopedia has a good section on screening shrubs, listing the various pros and cons. I would also seriously consider that the fastest growing hedges also tend to be the ones that require the most pruning to control size.

Simplest solution is to buy more mature(larger) specimens. You didn't mention a budget for this project. You don't mention the depth of area you are allowing for this planting. If you have unlimited space and good air flow you might consider staggering your row, every other one two ft. forward. I've done this and the shrubs grow much bushier. A good weeping hose placed between the front and back staggered bushes gives regular watering if you put it on a timer. The roots of the shrubs have more room to spread for nutrients and water done this way. And, each 'indent' gives you a marvelous spot to tuck some color like a Miss Huff lantana which will come back every year. I wouldn't tuck something like hydrangea in the indents ...they fight to grab water from the evergreens. I'd use hollies, but not Burfords.

I didn't know pinching the tips would make a yaupon denser. I'll have to remember that trick. Also didn't know that the males grow faster.---Hmmm. I do need them to be big fast though. While I love the intense red color of a Photinia, I probably won't use it because we had a gorgeous hedge of them at our old house, and one by one they developed fungal leaf spot and died.--Spraying with a fungicide didn't do a thing, nor did making the soil extra rich. I too have heard if you let Photonias grow to be the tree they really want to be that they're healthier, but for what I need, I can't do that. (There is a Photinia growing in the courtyard of Bedicheck Middle School in Austin that is phenomenal, but it has grown into a tree, not a bush.) I'll have to do some research on eleagnus because I'm not that familiar with it. Thanks for the suggestions.

Thuja occidentalis What plant to use to screen a view that grows fast, tall and very narrow is one of the most commonly asked questions. If the space is VERY narrow, the best solution is to put up a trellis and cover it with a well behaved evergreen vine like Trachelospermum jasminoides, Solanum jasminoides or Hardenbergia violacea. Another option is to espalier plants that have a habit of growing flat to begin with.Grewia, Xylosma, Podocarpus gracilior, and Cocculus being good choices.The other possibility is bamboo, but be SURE that you plant a clumping bamboo, rather than a running species, or you and your neighbor will live to regret it. Good clumping bamboos for screening are varieties of Bambusa multiplex. They have foliage nearly to the ground, are very dense clumps, and are from 6' to 15' tall. They can even be sheared. If there is a bit more space, a fastigiate shrub or small tree may be the answer. These are plants that have mutated from the normal growth habit, and grow much narrower than usual. Italian Cypress is the most commonly seen fastigiate plant, but there are many others that are potentially useful. Possibilities are Juniperus scopulorum 'Skyrocket', Deodara 'Gold Cone,' Juniperus communis 'Gold Cone', Thuja occidentalis 'Emerald', Buxus sempervirens 'Graham Blandy', Ilex crenata 'Sky Pencil', Ilex vomitoria 'Will Fleming', and Euonymus japonicus 'Chollipo' and 'Beni Komachi'. There ARE a few plants that naturally grow tall and narrow, Nandina, Mahonia japonica and Podocarpus macrophyllus are the easiest to find. If you are trying to extend the height of a fence, you could plant a large shrub or small tree alongside the fence, then prune up the lower branches to provide room to walk (and even plant) underneath. Photinias, Pittosporums , Oleanders, Arbutus unedo and Prunus caroliniana 'Brite n tite' and 'compacta' are good candidates for this treatment. The last (and most labor intensive) option is to plant a row of evergreen shrubs and keep it sheared to the width desired. Keep in mind frequency of shearing will depend on the growth rate of the plant. I have an evergreen privet hedge (one of the fastest growers) that needs to be sheared twice a year to keep it under control, and could use a third if I was a perfectionist and less lazy. I highly recommend purchasing and using electric shears to make the job more bearable. However, if you go this route, DO NOT plant a broadleaf plant like English laurel (electric shears result in mangled and shredded leaves that look awful). Highly recommended species for a sheared hedge are Pittosporum tenuifolium, Myrtus communis and Eugenia. You also need to think of what is on either side of the planting area. If it's an asphalt driveway or your neighbor's foundation, you don't want the heartbreak of having to remove your hedge (tree) 10-15 years down the road when it's looking perfect but starting to cause underground structural damage.