Question
We have recently put St Augustine grass both in the front and back yards.  It looked great for a while but now the large trees are doing a number on it.  How can I keep the sod thick and strong?  Maybe add seed of a different grass that will tolerate the low light?  

Answer
Hi Leta;
Could you prune out some of the limbs of those trees to let more sun onto the grass?
There is a low light Burmuda. I don't know what it is called.
My daughter put it in the yard of her place she had a few years ago. the nursery where she got it called it Golf Course Burmuda.
I'm sure it has a name for the variety.Maybe your nurseryman can get it for you. she sodded hers in though.
Another answer for you might be a shade loving ground cover. Under my big tree in my front yard, I have asian jasmine. It doesn't bloom when it is growing in the shade, but it is a beautiful small leaved , low growing ,evergreen plant. It spreads fairly quickly, but when it hits a sunny area, it grows like a demon. It also is growing up my tree trunk. It isn't covering the tree as fast as the English Ivy that was there before. so it will be a long time before I have to thin it off the trunk. It has been growing up the trunk for about 5 years, and is not close to endangering the tree yet.
If you want something taller, hostas would be beautiful there, and they love shade.Some varieties will take some sun or filtered sun, some need total shade.
Without getting enough sun to the St. Augustine, I am afraid it just will not ever flourish there.
I have St.Augustine too, and I built a low retainer wall, with Windsor Stone. I didn't want to chop off the edge of the jasmine with the mower, and get a choppy look, and I sure didn't want to have to fold the jasmine back over, to mow.
It was easy, I just had to lay the stones on the grassy area. You don't have to prepare a base like you do for other stones. There are several companies making this type of stones now. I have seen other brands at Home Depot and Lowe's. Up against the house in the shade, I have put in ferns and hostas. It really looks cool in there,and anything that looks cooler here in North Texas is very welcome. Actually it IS cooler in all that shade.It was a problem for years, until they started carrying hostas here.
For years it was too shady to grow my grass, but not shady enough for ferns.
We vacationed in Maine one year, and driving those shady highways, with the fern carpeted forrests, it felt so pleasant. I came home determined to get enough shade to grow ferns.
I am putting a front patio in that area, to put a park bench etc.
I think it will be a nice place to sit, enjoy the shade, and be able to have a place for neighbors to come and sit and chat.
If you want to keep the trees and the shade, you have to adapt to them. They will NOT adapt to what you want.
With all that shade, you can't have a smooth even grassy lawn, so best to decide what shady plants you like, and how you want to incorporate them.
There are many shade loving plants that flower. some of the hostas have gorgeous flowers. You can really create a beautiful yard there, if you just plan around all the shade.
Hope this helped some. If you feel I can help more, feel free to write me, anytime.
Charlotte