I second the suggestion on Ilex crenata--it really looks like boxwood and is easily trimmed. I find it's growth moderate. I have one large specimen and it seems always to need a haircut. There are other species of Ilex (Holly). Some of them native to your area (Ilex vomitoria)--but not sure of its growth rate. Photinia "red tip" grows very fast but I understand they suffer some kind of fungal problems in the South--especially when grown close together. I'm sure there are many possibilities for plants but the ones I have used for formal hedges include azaleas, Photinias, holly, boxwood, and Euonymous japonica.

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.

Pierce, just be aware that you will need a male holly for every 5-7 female plants to get berries. Because you will be planting tightly, you might be able to stretch it to one per 10 females. Most of the male forms I know of are shorter growing than the females, in general. You could get around this by using 1-gallon males and planting in the same hole as the females/'Nellie R.Stevens' as you space them out - they can grow up and be available, but are 'hidden' among the mass of the females. I know 15 gal. 'Nellie R. Stevens' are available, but can't speak as to price. While the 'Nellie R. Stevens' are a good hedge plant, if you wanted to mix in another type of tree, the Thuja 'Emerald Green' (a.k.a. 'Emerald Beauty' or 'Smaragd') is another good hedging plant, growing fairly fast to 12-15', and about 3-5' wide. You can fairly easily find 5 gallon plants, at about 4-6' tall - and pay more for them than 1 gal. - so they might be good where you want immediate height. While running bamboos will provide a solid screen once they are established, they will also RUN!! I have pulled out runners that are up to 8' long, and about 6" deep, in the spring. As long as you mow faithfully, you can keep them in check. However, even asphalt won't stop them from coming up - cement MIGHT! You can buy barriers, but you need to make a 3' deep trench for the barrier to be effective, and even then, you will probably have to watch for escapees over the top. Clumping bamboos are much better behaved, and will expand, but stay where you plant them.

My favorite shrubs for hedges are the hollies. There are many of them available and some get quite tall while others remain more compact. Their tiny flowers (so small you hardly notice them) are amazingly fragrant, and the birds love the berries, although they generally don't eat the berries until later in winter. Hollies are amazingly heat-tolerant, drought-tolerant and wind-tolerant once established. Dwarf Burford holly makes a really nice privacy screen along a fence line with the proper spacing, particularly if you let them reach their natural pyramidal shape and don't prune them. The use of the word "dwarf" is deceptive because they are dwarf only in comparison to regular Burford holly which is a huge monster. The dwarf Burford hollies we planted about 10 years ago are about 10 feet tall and each plant's spread covers 6' to 8' feet in width. We spaced them pretty far apart so they could reach their mature size without crowding one another. Another lovely shrub that is underused is Abelia. These are semi-evergreen, small-leaved shrubs that flower in spring. Their growth is quite dense and they are very drought-tolerant once established. I have a chaste tree in the backyard butterfly garden and the wildlife love it, and so do I, but it is deciduous and won't provide much privacy in winter. I've linked the website of Sooner Plant Farm for you because their website is amazingly informative. It has detailed into on many of the types of plants mentioned here, and photos for many of them, as well as many, many others. After you spend a little while looking at all the plants on their website, you'll have all kinds of ideas about what you could plant for a privacy screen. I second the idea that a mixed hedgerow is healthier because one disease can wipe out a monoculture of one plant variety. Also, diversity attracts more wildlife like birds and butterflies, for example. Dawn Here is a link that might be useful: Sooner Plant Farm