Let’s get this out of the way, when asked to formally post the colors in stands outside, don’t. Just don’t do it. Let’s look closely.
Most every colors presentation should not be a posting. Posting the colors is for a formal situation and an outside ceremony either should have the color guard itself post (standing off to the side) or just enter, formally present for the anthem, and then depart without posting the flags. This type of presentation is called a Show-n-Go and should be the most common sequence for the color guard. See All About Posting and Presenting the Colors.
Every public event should have an American flag displayed somewhere. Since the ceremony is outside, is there a flagpole nearby? If so, that requirement is covered. If not, you may want to pre-post an American flag with some heavy weight around the stand. Having a color guard come in to formally present and then leave is perfectly acceptable.
Low-neck flag stand
High-neck flag stand
Back yard umbrella stand
The trouble with the low-neck stand is that it does not adapt well to being outside, even if heavily weighted, since there is little support for the staff. This can be remedied by adding a tube (see Color Guard Flag Stand Problems Resolved). The high-neck stand has a bit better stability, but still cannot handle wind gusts. What may be best is a backyard umbrella stand that can be filled with quite a bit of sand.
The photo at the top is the weight and stand system used in and around Washington DC. This particular photo is of President Kennedy’s grave at Arlington National Cemetery where the flags are posted for the day to commemorate his birthday.
For the preposted flag… No fringe. Fringe frays easily. Fringe attached to the American flag goes against the Flag Code anyway (see Flag Fringe and Finial Theory). An embroidered rayon banner material will be destroyed in windy conditions. Use nylon, 2-ply poly or Supratex. Also no streamers, for the same reason: once they get frayed a bit by the wind, they turn into a ball of thread. And they bleed if it rains.
DeVaughn Simper, Vexillologist (Professor Flag), contributed significantly to this article.