If you were in zones 6 7 or 8 with decent rainfall I vote Metasequoia for normal green or its cultivar "Ogon" for a yellow/lime highlight like little else.

With your ocean dominated climate they MIGHT do. How little rain do you get 20 inches yearly?

Japanese maples (my favorite!), magnolias, flowering Cherry

All east Asian monsoonal climate plants so apparently site is not too dry. And you would be able to use other trees needing a moist soil in summer. If you like maples maybe another kind of those, there are many. What communities are you near? I may be able to suggest a labeled collection where you can look for candidates (maples or otherwise). For example:

http://www.gardenbythesea.org/

Thanks everyone. About 15 inches annual rainfall :( I just decided I should announce the "winner" when I plant!

Do not plant metasequoia then. Just curious, what is the tallest tree you see out there that does not require irrigation?

It's a newer yard landscape, so I've set them all up on drip lines. Will shut off the drip after they're established and use for dry spells.

You're not going to be able to go without watering Japanese maples etc. - if you want to get by on natural rainfall and you only get 15 in. then you should be looking at California natives and other Mediterranean climate plants.

Agreed. It seems as a whole California has too many yards, fields and people for its (and the Colorado river's) water supply. Try not to plant anything you will have to water to keep alive unnaturally for 50 years.

Sorry guys/gals. I completely understand your perspectives about the water & didn't want to turn this into a political debate. The ground where the tree is intended stays relatively moist due to mulch & overcasting shadows. There is plenty of moisture there after the tree stabilizes, unless we have some dry spells that need occasional watering until the roots are established. As mentioned, I'm coastal California, so we get heavy fogs that help moisten the topsoil daily. Our summers are never hot. A hot day for us is 80 degrees. Residential water usage is negligible for our state's shortage problems in California. Our state is vast with many microclimates -- not just all desert. I am a fan of dry-landscaping myself, and I'm the first to rip out grass because of the excessive watering. My thirstier trees are thriving because they use my neighbor's lawn. Actually, I despise grass in California -- love the look, but throwing water on the ground for ground cover seems a little nuts to me. For ground cover, I use sedum. Love that stuff!! We can even drive over it and it doesn't get hurt. Our dry spots we also use lots of other succulents, and I just put in a dry river creek. It's beautiful. We are pushing for our neighbors to do similar, and we are working hard to inspire others by setting an example -- showing that yard can be both conscientious & beautiful. It's hard to make suggestions without offending people, especially when everyone knows that shutting off the water to just our almond farms would fix our water shortage. It's not exactly easy having these discussions when one of the neighbors is a well-known farmer (obviously not one living at the farm). I love trees because they are beautiful, and many will live for years after their roots are established without the need for ongoing water. I'm not so worried about the rainfall because I utilize the micro-climates of each space within the yard. I also like the trees because there is an erosion problem adjacent to our lot (sadly, people were formerly dumping trash there) that I'm hoping will eventually stabilize from the tree roots. Our friend is a plant geneticist who has some succulents that thrive extremely well with no water that we plan to throw out there to further stabilize the topsoil. I've hired landscape architects and have been disappointed. I've always found that if you have high standards and can do a little independent research (everything is online these days), you're going to do a better job for yourself than others will do for you. Does anyone want to recommend a California native tree? Don't worry, I'm not going to plant it. I will research it first ;)

I think the fastest growing tree you could plant is a hybrid poplar.....something like 8 feet of growth per year.......plus it can only reproduce by cloning so not invasive

My sense of scale for your project was entirely off! My suggestion was going to give you a thirsty 100 foot neon yellow tree. You seem well versed in the reality of your environment.

Now it has been since '07 but I went to this botanical garden plum in the middle of the Phoenix desert. A way drier and hotter environment than you have. Even them folks had 100's of plants so I know we will find something.

I just wanted to thank everyone for all the tree recommendations thus far!! Although admittedly, I'm not going to plant the ones suggested, I really appreciate everyone's recommendations. Even if it's a little unlikely for me to select the tree from this forum, I'm still enjoying researching more information from everyone's special recommendations. Yes, I've visited many different places for inspiration, but I also like seeing what others suggest from just a written description. Thank you, everyone!

Here are some nice evergreen trees that are suitable:

Corymbia ficifolia (a nice red blooming tree)

Callistemon rigidus

Juniperus scopulorum 'Tolleson's blue weeping'

Grevillea robusta

Acacia baileyana 'Purpurea'

Eucalyptus deglupta (has really cool bark, but is from jungle areas, so it might not like dry areas)

There are also tons of silver leaf Eucalyptus species to select from also.

Poster is in Zone 9, you have at least 2 on that list that will not persist there due to periodic winter cold events.

I knew the poster is in zone 9b

Corymbia ficifolia -- zone 9b

Callistemon rigidus -- zone 8b/9a

Juniperus scopulorum 'Tolleson's blue weeping' -- zone 4a

Grevillea robusta -- zone 9a/9b

Acacia baileyana 'Purpurea' -- zone 8b/9a

Eucalyptus deglupta -- zone 9a/9b

Corymbia ficifolia and Eucalyptus deglupta would be the most likely to suffer longterm if there were any deep cold shots below around 20F, but they still could have a chance longterm especially in any warmer microclimates.

I live on the west coast and am familiar with where these trees are seen as persisting landscape elements and with what it is possible to grow in northern coastal California.

As anyone knows I'm not a "natives uber alles" kind of guy by any means, but if you're in the perfect climate for Catalina Ironwood, why not grow it? They are some of the most arrestingly beautiful trees of North America. I'm not sure pictures can capture what it's like to be in the presence of one of them. Though I don't know how long they take to get the picturesque appearance of the older ones.

Ok -- what do you guys/gals think? I was thinking about a ginkgo biloba tree (male variety). Although some variations seem to exist in the literature...for the most part, they are drought resistant, can do well in sun, withstand high winds, thrive in zone 9, and appear quite stunning in photos. Some people have said they are low-maintenance, too. Thoughts? This seems like one of those magical trees...tall, unique foliage, canopy. I welcome your feedback.

Yes those make distinctive "character" specimens but are slow to develop, if that matters.

One more vote for Ginkgo biloba. They are incredibly hardy (tolerant of drought, heat, cold, pH, and poor soil--though not of poor drainage), and are low-maintenance, very long-lived (many centuries), and quite stunning in appearance. This is a high-quality tree that should be planted more. They are indeed very slow to establish and may not grow much initially, but then most cultivars can put on a reasonable growth rate (maybe a foot per year) in good conditions. Cultivars that you might want to consider include 'Autumn Gold,' 'Saratoga,' and 'Magyar.' If you're looking for something more narrow, consider 'Princeton Sentry.'

Ginkgo biloba is one of the most pest and disease free trees in the world. I own a male cultivar. They are pretty slow growing however. They usually only grow 1 to 2 feet a year. In a dryer climate such as parts of CA, it will probably be about half that rate (0.5 to 1 foot a year or less).