Upside down lawns are notoriously difficult to water, especially this time of year. That could be your problem. :o)

Most zoysias require full sun. I'm experimenting with an outrageously priced variety of a manila grass (zoysia) called Shadow Turf, from the Turffalo people in Lubbock, TX. It is supposed to be much more shade tolerant than other varieties. I thought I had a shady area, too, but the bermuda is growing like gangbusters in there. I'll be reporting back more about the Shadow Turf as winter approaches (probably late December for us). So far the Shadow Turf is as invasive as bermuda, but much easier to pull back out. Of course it have it planted in pure sand, so neither one is very hard to pull out. The Shadow Turf color is much greener than the common bermuda's blue-green. It will be interesting to see which grass wins as they merge together. Right now I'm pulling the bermuda out of the Shadow Turf while it becomes established, but as it invades the bermuda, I'm letting that happen. If you are thinking about Shadow Turf and worry about the cost, I got about 1 square foot of plugs for $90. I covered about 20 square feet with plugs. It sat seemingly dormant for 2 months and all of a sudden, exploded into full coverage in a 2 week period. I am at the point where I could remove plugs from my sod and transplant into other areas. Another way to do it would be to cover more like 100 square feet with the initial plugs. They WILL provide coverage once they reach the exploding stage of life. Still I'm used to paying more like a dollar per square foot for real sod (immediate coverage), so I had to swallow hard to spring loose for the cost of this turf. Good thing this is a hobby.

it has to be planted in "plugs", correct? Incorrect. There are many varieties available as sod. There is no Zoysia grass seed? Incorrect again. Compadre and Zenith are available from seed, however I doubt it would germinate in your area, nor would you be happy with it. I hear it likes mostly sun, can't tolerate shade. Incorrect again. Zoysia can tolerate some shade and one variety called Shadow Turf can tolerate and thrive in 90% shade. However it is only available in plugs and you could not afford it. Also it turns brown at the 1st hint of cool weather. Yes and No as it depends on the variety you are talking about. In your area I would only recommend Myers (Z-52), or Emerald. They are very cold tolerant, and both available in sod, plugs, and sprigs with excellent shade tolerance. I strongly disagree with Texasredhead with the statement "Zoysia will not tolerate foot traffic". Zoysia is among the most wear tolerant grass ranked right up there with Bermuda grass. However, with the slow rate of growth gives it only fair recovery. Therefore, they perform good on lawns, golf course fairways and baseball fields. But, they are not recommended for football or soccer fields where traffic is concentrated. If the grass is completely worn in those areas, zoysia is very slow to fill in the damaged areas..

I put in zoysia March 09 in a large area, mostly shaded (probably 20% later afternoon sun at most) with a couple of patches that get mostly sun. The shaded areas grow best. The sunny area dry out super fast and I have to do a lot more to keep them up. It has mostly crowded out the weeds in the shady areas. Not 100%, but it's getting there if I keep up with the maintenance. This pic is fairly recent. I'd just cut down two trees - one by the street and one behind the playhouse. That gives a lot more sun and since then, those patches hit by the direct sun are not doing as well as the heavily shaded areas. The area in the foreground gets the most sun late afternoon and has a fair bit of weeds, but since this pic was taken (late May), I've managed to control the weeds better. Also, the whole area was one big field of weeds before I started. I removed some, but not all, so figure we'll be fighting weeds for awhile. The whole area is still a work in progress.