|A pretty young plant floating in clean water|
|This is a good size for using the greens|
Brought to North America by early colonists, a number of sources agree there were none here before 1620 when the Mayflower arrived but that they were common by the 1670's. Anyone who has ever blown a dandelion seed head to the wind can attest to how easily they spread so this isn't too hard to believe. At one time the much maligned flower wasn't considered a weed at all and can still be found in produce aisles.
As for uses, the most simple is to take the youngest leaves you can find and cook them like any other green. They're similar to spinach with a bit more flavor. Larger leaves can be bater dipped and fried to make fritters or cooked with eggs to make frittata. The greens are usually a little more bitter than I like for salad but I've done everything with them from baking them into bread to adding them to quiche. I think one of the most interesting uses is using the roots as a coffee substitute or to stretch coffee the same way chicory is used. By itself, again, much like chicory, tastes a lot like burnt pencil shavings by itself but adds a pleasant smokiness to dark roast coffee.
As a cultivar it's one of the easiest things in the world to grow. I'd suggest either gathering them wild or replanting each season. The taproots get bigger over time and will cause even young greens to taste bitter. I've not tried to trade them but you might even find some vendors at farmers markets are interested in them once they get to know you a little and are assured you haven't gathered your plants on the side of the road or next to where you store your mower gas. If you have a patch of lawn you aren't using you might even consider sewing it with dandelions for a care free food crop that will literally take care of itself.
Some cautions might also be in order. Namely that some people are sensitive to a latex like compound in the leaves and stems. The white milky liquid was even explored for use as a rubber substitute during WW2. So, if you are new to eating dandelions it might be wise to try them cooked first and in small amounts. Another thing to know is that they contain diuretic compounds. So be careful with this plant until you know how it might effect you. The white sappy stuff is also what gives them a bitter taste as they get bigger. I have never heard of a non-edible variety but there are a few plants that look like dandelions. None of those I have encountered were toxic but they also wouldn't be considered desirable to eat.
When I gather, I typically toss the plants into a bucket of cool water. Some people suggest salt water, I'm not sure I'd waste the salt but it might help draw more of the bitterness out of the plant. I haven't tried freezing them but I'm sure it'd be much like freezing spinach. They're best used fresh.
This post is more intended to encourage exploring the use and cultivation of dandelions rather than serve as a recipe hub but if anyone is wants them email me and I'll post a few but there are many many recipes on the web just simple Google search away. I've also had success simply substituting dandelions for spinach in most any recipe I've tried.