Some dragonflies can be found quite a distance from water, especially on cloudy days - it sounds as if you are already attracting them to your property.

I'm not aware of any particular type of plant that they prefer. I get the most in the un-mown areas of my yard, I would think that it probably provides the most insects. And they do like to perch on the tall stems. I also get cruisers that cruise back and forth across the hill where the grass is mown. They tend to perch high in the trees. The eastern amberwings seem to prefer shorter vegetation that is a little sparser.

Dragonflies are like so many other species in nature, there is a niche for them all! So I'm not sure there is any one plant that is good, I think a variety of vegatation is probably the best.