A palm tree is about the only tree that won't drop leaves, etc., for next to a pool. Not having a pool, I will pass on other suggestions.

For the front, how tall/wide do you want this tree to be in 15 years or so? I can think of several nice ones, but without any parameters, it's hard to give advice. Where in California are you? This would also affect what I might suggest - a tree that would thrive in Santa Barbara might struggle in Eureka, and vice versa - I am assuming more southern than not, what with the queen palm, but.... With a little more info, including what direction/exposure the tree will have, and thus the amount of light it will get, and what sort of soil, sandy, clay, etc., I am sure you will get a lot of suggestions.

First, the birch was not "spewing sap". What you experienced was the dripping of honeydew or the sticky excrement of aphids, which are an exceedling common problem with birches and restricts their use around driveways (a mess with cars), entries or any outdoor entertaining area.

Second, what you outline is a rather restrictive situation that is not well addressed by something as broad and diverse as an international Internet forum. Obtain a copy of the Sunset Western Garden Book, which is a must-have for anyone gardening on the US west coast. It has a listing of plants suitable for use around swimming pools. There are virtually no trees - other than palms - included in this list as virtually any tree will drop litter of some sort and most will easily clog pool filters and become a nuisance. Even palms will drop some litter - old fronds, leaf casings, fruit, etc. but it tends to be less than many other choices. Narrow growing conifers - like Italian cypress - planted at a reasonable distance away can be effective, but more for screening than any shade provision. And the scratchy foliage of many conifers is not a pleasant sensation for nearly naked swimming suit-clad bodies so be aware of that feature as well.

Finally, since pools are pretty much omnipresent in much of SoCal, your situation is not unique. Local nurseries and garden centers must deal with it constantly, so access a few of them in your area for further help and suggestions.

Well, actually, Gardengal, it may have been sap, although 'honeydew' is more likely. My head got dripped on at several locations in my SIL's garden this spring, standing under the river birches - twig ends had been damaged a few weeks previously as branches fell in a heavy wind, so, just as tapping the trunk can give you sap (to boil down for syrup, which is said to compare to maple syrup, but take more gallons as it has less sugar), the twig ends were dripping as the sap rose. We moved over, there was nothing under the trees except plants, gravel or grass, the sap stopped dripping eventually, and no harm was done. I can imagine that the sugars and other constituents in the sap might well allow for mold growth, which could stain concrete, if they didn't stain themselves.

Snookums, I see, on re-reading, that you do say you are in inland southern CA, so ignore that request. But, it would be a large help in making suggestions to you if we knew a bit more about whether the front tree would get morning sun or shade, all day sun, or what mix of sun and shade, as well as how large a tree you, and your DH, want to end up with, and the type of soil you plan to plant it in. Do you want a tree that flowers, do you want a tree that has berries, or good fall color - harder to do for So. CA, as many that do well with the heat just don't color well? Do you want a tree that stays small, or one that can get over 60' tall, and do you want one that stays taller than it grows wide, or one that gets pretty wide? Do you want a tree that casts heavy shade, or do you want lawn and a garden/flower bed under it? Knowing these things, you should get several suggestions that fit your wishes. You can then do more research to see if A. it will do well for you, B. it can be found in your area, and C., but most mportant, if both you and DH like its looks!

Ew - excrement of aphids? Ick, ew! Any suggestions on how to get the stains off of the concrete? It hosed right off of the patio furniture pretty well, but left purple-colored round spots on the cement, each about 1-inch in diameter.

Definitely not a fan of Italian Cypress. I don't like the way they look when they get too tall, and we'd only have room to plant one.

I'm now really leaning towards the Queen Palm in the back. Any suggestions for the front yard tree? The ornamental plum we have doesn't drop too much other than leaves and flowers here and there, but we do want the roots to be on the shallower side. It's about 5 feet away from the driveway. How do I want it to look in 15 years? Mature, but not overgrown, and my driveway still intact.

We are in inland southern California, but not quite desert. The soil is clay. Both areas get a lot of light.

Dibbit - seems we posted at the same time. The tree in front is on a patch of grass that is about 10 feet wide and 15 feet long, with driveways on both sides of it. So it can't get too wide so we can park our cars. I probably don't want a tree that can get too much taller than the house. (2 story) - it just seems like it would look odd. The only shade in that area is the shade under the tree. Sun pretty much all day. I don't care whether it turns fall colors or not - that's not a big deal to me. There won't be a garden or flowerbed underneath it - just grass.