I don't live in that directions, but I can help with a couple of these questions.
1: The reason the grass doesn't grow well around your tree is because it isn't getting enough sun. Putting sun-loving lantana probably isn't the best choice since it needs a lot of sun for the best blooms. I agree you should create an island bed around there, but maybe something that can tolerate a little more shade. How about Turk's cap? It will give you pretty red blooms in the shade. Or simply use a groundcover like liriope, English ivy (although, don't let the ivy grow up your tree), etc. There are a lots of good plants that will do better in the shade than lantana.

2: If you have plenty of sun on that fence, why not plant some thornless blackberries? That would be a perfect support for them, even though they will grow taller than 4 feet, you can let them arch over the fence and maybe share a few with your neighbors.

3: I think you might want to figure out a way to get that water to drain off, if it means filling in the area with some topsoil or whatever. I'm not sure what kinds of shrubs like "wet feet", but I'm sure you'll get plenty of suggestions.
4: Like I said, I don't live down that way, but I know plenty of people here that are that direction, so they'll be able to give you some advice on some of the best nurseries down there.

Congratulations on your new home! Although we live fairly close by, I am sorry, I don't know about nurseries nearest to Alvin. We go all around the area, quite often to Maas Nursery in Seabrook.

1) Denisew's suggestions about the area by your willow oak are good. There is a type of grass - I think it's spelled acorus - that might look good by that tree, in addition to plants like liriope and monkeygrass.

2) Try "Arapaho" blackberry - we have a thornless variety that seems suited for the spot you describe. Ours has produced well.

3) Wax myrtle is an excellent choice. Be ready to deal with many suckers or watersprouts - quick-growing shoots that emerge from the base of the plant. Train the WMs as shrubs with 3 to 5 main trunks. Without seeing that wet spot you describe firsthand, I could not advise on what tools you need to clear the area. You might want to use the natural tendency of at least part of the area to do a rain garden. (separate forum) For areas that get wet but are more sunny, we have found that Gulf Muhly grass works.

Good luck and have fun!

Word of caution. When you plant under the tree, do not add more than 1" of fillers like compost. The roots of the tree can be smothered. If you mulch the area, do not let the mulch collar up to the tree, pull it back so that the swelling of the tree base is exposed. That is Howard Garret's advice anyway.

That vine crawling on the ground, is it poison ivy or something not as bad?

RE: 1) There's a huge willow oak in the small south-facing front yard, and since the lawn doesn't grow well around the base, I'm thinking of making a little island and planting something, perhaps some lantana.

I would not build an island around the base of the tree. Don't add any soil or anything for that matter around the root flare, where the tree starts to get wider as it goes into the ground, that could encourage root growth that can girdle the tree. Also it amounts a grade change which trees do not like. The roots close to the top of the soil need to be able to respirate.

Hi Mark, welcome to Alvin. I guess that I won't recommend that you build a raised bed around your willow oak, since everyone else, including this Garret guy, some are constantly quoting, think it will spell certain doom for your tree, but....,I'll tell you what I did, and then let you decide for yourself what you want to do. I have a water oak in my front yard. Two years ago, I built a 10" raised bed, about 10' in diameter, around it. I plant shade loving plants in it. Impatiens, Mona lavender, begonias, etc.. I have seen no ill effects to this raised bed, in fact the tree just keeps getting larger. This bed does require more water than some other beds because the tree tries to suck up all the water. I built a similar bed around the pecan tree in the back yard, and it is doing fine also. Maybe it will take several years for these raised beds to kill these trees, but for now they are fine and I have what I want.

I don't know of any good nurseries here in Alvin, but there is Joseph's, between Manvel and Pearland, and as stitches said, Maas Nursery in Seabrook. Maas is my favorite.
Jim

I built a raised bed around a red oak in my backyard about 8-10 years ago, and my tree hasn't died yet either. I believe this issue of raising the grade around a tree pertains to using native soil, especially clay soil. That COULD smother the roots. If you use light materials like compost or bedding plant mix or a landscapers mix, and don't use TOO much material on the top of the roots, in my opinion, you should not have a problem. Turk's cap is a great shade plant, so is hinkley's columbine, and cast iron plant (aspidistra). If there is really heavy shade under your tree maybe you could try removing some lower limbs to get some sun into the area. Have a great time planning your new landscape!

Wow! Thanks for all the great advice! It's wonderful to have so many suggestions.

I did pick up some liriope today, but I didn't have any luck finding turk's cap or wax myrtle, so that'll have to be another trip.

debndal: landscape mix was what I actually bought (before reading your post) which was purely a lucky guess because I have no clue which soil mixes are "heavy" and which are "light." I'm a little confused by your comment about not using too much on the roots. If I'm doing a raised bed, wouldn't it be uniform thickness everywhere? Or do you mean that I shouldn't let the bed extend out too far from the trunk?

bossjim: thanks for the nursery recommendations. Sounds like it's time to pay a visit to Seabrook. Just out of curiosity, when you built your raised bed, what material did you use for the sides?

txgardenlady: I do have some vine by the back fence that looks like it might be poison oak, but the vast majority of the ground vine is something else. Whatever it is, it is very, very invasive -- all over trees, fencing and ground. Pulling it up is quite empowering; it feels like "freeing" the ground from the evil vine :)

Mark, I used "Estate Edge", 2 high. It's those stack-able brick looking things. I got them at Home Depot. I first rented a sod cutter, removed the sod, then tilled as deep as I could. I had Good Earth deliver truckloads of their "flower bed mix", and filled the beds. I say truckloadS, because I was building lots of beds at the same time.
Jim

You could have that invasive honeysuckle, or Virginia Creeper. If you can pull it out that is good, poisoning that honeysuckle doesn't work for me. Just knocks it back for a few weeks.

Another shade plant is Bear's Breech (don't know the formal name). It is very tropical looking and shoots up a flower about 2 foot tall. If you want something smelly, and don't mind the watering, butterfly ginger is a good shade plant.
Columbine, Oakleaf hydrangea, snapdragons, holly or autumn ferns(there are others) are all good.

I definitely would not bury 10" of trunk, no matter what material. Basic tree care says that's a big no-no. Some species will tolerate this insult better that others. And some will not show ill effects for many years. But it is an insult, even if not fatal.

Actually, probably the most important aspect of tree installation is leave a visible root flare.

I can't speak for Mark, but in my case, it's about what I want, and not so much about what the tree wants. If my trees have been insulted they don't really show it.
Jim