I don't know a lot about trees, so hesitant to comment. I do know that the crape myrtle 'Natchez' makes a great shade tree. It can get up yo 30 feet tall and when not chopped off, has a wonderful canopy. It also has pretty cinnamon colored bark in the winter. I had one at my old house and have just planted one at my new house. Crape myrtles are fairly fast growers. One down side, when in bloom, they weep, so you don't want to sit under them or plant to close to a driveway or you'll have to keep cleaning your windshield!

I've been told water oak is a good tree for that area.

I've read the beautiful Jacaranda tree can survive in zone 9. I lived in San Diego for many years where they were used prolifically as boulevard trees in many areas. It's hard to believe they could grow in the Tx heat.

Jacarandas aren't entirely reliable in Houston. If you want an exotic fast grower, you would do better with a purple or white orchid tree (Bauhinia) though they can get knocked down to the ground in a hard freeze. (They aren't *quite* as tender as the jacaranda.) I have seen orchid trees grow 4-5 feet in a year.

The Princess tree (Paulownia) is also showy and grows fast, and should do well there, being more cold tolerant.

Good shade trees might include Bradford pear, red oak and sycamore.

Check out TAMU's site:

http://texastreeplanting.tamu.edu/CustomSelector.aspx

I'm from the DFW area, but for fast-growing and long-lived up here I would go for some type of Oak. We also have 4 Mexican Sycamores in our yard, and they are huge and very pretty. They do drop bark, but that doesn't bother me. They may be happier in your zone as they struggle in dry summers here.

I planted a water oak here in Houston, and it is a fast grower and huge. I love it. However, all my grass is dying underneath, and I'll have to figure out how I want to handle that. I have it pruned at least annually, so the canopy lets light through, and it is still pretty heavy shade. Which is fine...that's why I planted it.

We also have a water oak ( I think they are also called Pin Oaks sometimes). The builder planted that and a Loblolly pine in each yard because they are native to the area. I wouldn't recommend the pine though. They drop limbs pretty often. Also the pine cones are a nuisance.

You might look at a Nuttal red oak too. My daughter planted one in her yard and it's doing very well. It grows wild in their green belt.

How damp a site? Water Oak will only grow well on damp sites. And we're talking about canopy trees in full sunlight, right? Oaks are decent growers, but here are some that are even faster:

1. Loblolly Pine

2. Sugarberry

3. Winged Elm

4. Red Maple

These are what are called pioneer species. They take off when there is a clean slate.

If you have a very damp site, you can also count on good growth from Sweet Gum - even faster than Water Oak.