You need to pin down your requirements/preferences if you want a more targeted answer. Such as, evergreen or deciduous, drought tolerant or not, flowering or not, fragrance or not, mature size preference, etc, etc. Get yourself a copy of the Sunset Western Garden Book and look at the sections on tree recommendations for patios/gardens. They break the choices down by zone, type of tree, and all the other characteristics are listed in an organized way to help you decide.

Also, southern California is a bit too general of a location, as the climate varies widely over such a large area. Tell people what town you actually live in, do you have trouble with high velocity Santana winds in your location, and perhaps what else you have in the same vicinity of the desired tree location.

bahia gives good advice. Just to add if you are a beginning gardener the Sunset Western Garden Book is very helpful. If you don't want to buy it, nearly all libraries have it.

Thanks for the response. I will get that book and try to provide more info. In the meantime, to respond to a few questions that I have an answer for: I live in Irvine in Southern California. My top-most priority for the tree is that it should be easy to maintain (want to spend minimal time cleaning up fallen leaves/flowers). Fast growing, fragrance, flowers would be nice also. Not sure if I should be concerned about it been drought tolerant or not. I have lawn in the surrounding area, which gets watered regularly, so watering won't be an issue. Hope that helps.

Below are some pics of the corner where I am planning on planting it.

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Please consider a "water-wise" tree for this corner in your yard. You will be glad you did, we all have water issues in Socal.

Ah, a neighbor. I'm in that area of OC myself.

Does it have to be evergreen? Crape Myrtles are very nice, beautiful flowers in June, not too big, not too messy. There are many different colors.

A favorite of mine is Agonis flexuosa 'After Dark', which is evergreen, dark foliage with white flowers, again, not too big, and well behaved roots. This is a particularly clean tree. I have a couple, and they're beautiful.

How about an Orange tree? You want fragrance, there is nothing better than the scent of orange blossoms in the spring. Heavenly. Again, not too big. And if you like oranges, there you are. Valencia probably, you may not have enough heat for a Naval. They like more heat.

A fruitless Olive. I think the most fruit-free cultivar is 'Swan Hill'. You want a fruitless one if you want cleanliness. Olives are a very beautiful tree.

Arbutus unedo is a beautiful small tree, but somewhat messy due to fruit drop.

A small Magnolia, I believe a common small cultivar is 'Little Gem'. The regular common Magnolia would be too large! If you select so, make sure you get a small cultivar!

There's a native large shrub that functions well as a small tree, Heteromeles arbutifolia, common name Toyon'. Grows fast, tough, gets large enough to be a nice evergreen small tree with some judicious pruning. Does have red berries around Christmas, hence another common name, 'Christmas Berry.

Pacific Wax Myrtle?

I do not recommend the native Cercis occidentalis. What a mess! I'm not happy with mine.

Brisbane Box, Lophostemnon confertus gets fairly large but can be kept headed back easily. Not my favorite, but common, tough, fairly well-behaved.

It should be noted that flowers drop, so the more flowers the messier the tree tends to be. So keep that in mind when making your selection, if cleanliness is extremely important.

Whatever you plant, I wouldn't put it too close to the walls lest your neighbors either complain or hack it back to your property line.

That's a pretty small space. I'd go with a dwarf citrus- they look beautiful, smell divine, and give fruit to boot!

Renee

Dare I say it. Oleanders make nice small trees. But would not cast a large amount of shade.

I have a peach tree that grows beyond the fence. That neighbor cuts off overhang branches. And throws them into my yard. I would think he'd love free peaches.

Lawn watering is not a postive for trees. They need some deep irrigation to encourage deep rooting.

Another fact of fast-growing in regard to trees, not shrubs trained as trees, is height. Every fast-grower I know maxes out way too tall for a city lot.

Pyrus kawakamii is a good looking tree to sit under and to view.

Where are you thinking to locate the tree - inside or outside of the concrete edging?

Tristaniopsis laurina 'Elegant' might be a good fit for your situation, no fragrant flowers, but a well behaved smaller sized evergreen tree.

Thanks for all the input. I did manage to get the Sunset book and will look up all the suggestions in there.

iris_gal - I am looking to plant the tree inside the concrete edging (between the wall and the concrete edging)

Thanks for the suggestions hoovb. I looked up the trees that you suggested online:

Crape Myrtle - Looking at the pictures online, the tree is not dense enough. Would it be a good shade tree?

Valencia orange tree - This sounds like a good idea. Is the stem long enough so that it clears about 6'? I just wanted to make sure that the overhang of the tree clears the fence.

Fruitless Olive, Heteromeles arbutifolia - Doesn't seem to
have a long stem.

Small Magnolia - Looks promising as well.

Thanks for your suggestions.

Flowers, but no fragrance, and deciduous; also drought tolerant the native desert willow (Chilopsis) is a nice small tree, or the hybrid Chiltalpa. Another to consider, again for just flowers and drought tolerance, Vitex.

wanda

Bitmaster, you prune orange tree trunks up to the height you want. Mine is high enough to walk under, but my neighbor has kept his so that the branches touch the ground.
Renee

Deciduous choices:

1. A small native tree, cercis occidentalis (Western redbud). Gets to about 15 feet. Usually grows as a multi-trunk. Usually blooms better inland where it gets colder. Attracts hummingbirds. Doesn't bloom heavily near the coast where I live. Rounded shape and leaves. Well-behaved rootwise. Mine is 5 feet from our pool.

2. Chaste tree (vitex agnus-castus). Great, reliable summer bloomer, even near the coast. Attracts hummers and butterflies. Roots well behaved--ours is also 5 feet from the pool like our cercis occidentalis. To about 15 feet. We've grown ours as a multi-trunk. Some people like to keep the tree trimmed as a large shrub. (You can see a small portion of the Western redbud in the foreground to the left.)

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3. Forest pansy redbud (cercis canadensis). This one blooms better (at least in my location) than my native redbud.
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Cercis are messy! And mine reseed EVERYWHERE. I pull out thousands of them.

Crape Myrtle - Looking at the pictures online, the tree is not dense enough. Would it be a good shade tree? Yes, they cast nice shade to sit under. If the shade is too dense, you'll kill your grass.

Valencia orange tree - This sounds like a good idea. Is the stem long enough so that it clears about 6'? I just wanted to make sure that the overhang of the tree clears the fence. as Renee said, you limb them up as they grow

Fruitless Olive, Heteromeles arbutifolia - Doesn't seem to
have a long stem.
you limb them up as they grow

Another idea would be the fruitless Loquat, Eriobotrya deflexa. (Not the fruiting one--that can make a mess).

Thanks for the reply hoovb and hosenemesis. It helped clear up my questions.

I can only give recommendations for trees that I grow in my own yard. If you live in Orange county, I think they would do fine there as well.

All three trees have this in common:
They are drought-tolerant
They are upright and moderately narrow
They are evergreen and not messy. They do lose older leaves occasionally but mostly neat and not messy
They flower seasonally

The trees are:
Stenocarpus sinuatus moderate grower
Metrosideros Gala moderate/fast grower
Metrosideros Springfire moderate/fast grower

If I was to put a preference to your conditions, I would pick Metrosideros Springfire.

-Ron-

Thanks everyone for the valuable input. I finally got around to making the decision and went with Little Gem Magnolia. Here is the picture of the new tree:

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