Dragon flies like a water feature with unmoving water. Plant a whisky barrel bog garden and use the BT dunks to keep the mosquito larvae away and you'll see tons of dragonflies, and maybe even some tadpoles too.

The first time I saw a dragonfly in my backyard was when I had a purple heart plant (its an annual here, thankfully it overwinters) I've also read that sweet alyssum, queen annes lace, and dill all attract benificals.

It's not that dragonflies like water, it's that they need water. They lay eggs in the water and the nymph stages are water dwellers until adulthood. They aren't attracted to plants because they eat small insects such as mosquitoes. The best way I know of to have dragonflies is to live near a water feature (spring, river, lake, pond, creek) that is not contaminated by pesticides or other residues that will harm their eggs and nymphs.
For other beneficials in general, herbs seem to be good attractants.
Mrs H

Here's a link to our new (1.5 years old) fact sheet on beneficials. We didn't cover much on dragonflies (the focus is on the home garden and landscape) but we've had good feedback on the information in the document.
Regards,
Colin

Here is a link that might be useful: UMaine Fact Sheet on Beneficials

There are a lot of species of Dragonfies
Some are called bog hunters, these will normaly feed over small ponds etc,

Another group is called stream cruisers that hunt for food over slow moving streams

Another group are night fliers, that is they only hunt at night about 18" to 2 ft off the soil line.

There is another group called sitters, they sit on a leaf, post, or car antenna, when a bug flies by the jump up to get it, and then return to their perch. These are fun to watch

These, if you are very patient, you can get them to walk of a leaf and onto your hand. ~ what an awsome high ~

Then there are High Flyers, they fly about 10 to 30ft off the ground. Mine are usually around when when flying ants migrate, Then my sky looks like the last air raid scene from Tora, Tora, Tora..

Dragonflies eat softbodied insects from fungus gnats to house flies and everything between. They have been eating May flies since the Jurasic era, ( the only 2 insect survivors) Best is that also eat Maine blackfies and skeeters.

To have dragonflies in your garden, you will need to stop using the high powered insecticdes for about 3 years, Your local ponds and rivers need to be free of nitrates and pesticides.

You need to accept some insect damage on your plants. But after another 3 years it really pays off, I killed less than a dz bean aphids this year,

For a fun read, search Green Darner, This little 1 5/8" long insect flies from the Maritime provinces of Canada to somewhere in South America.

Byron

Here's an interesting article from Mother Earth News Maga-
zine regarding how to attract beneficial insects.

Swanz

Here is a link that might be useful: Let bugs work for you!