Finding chicory is really easy this time of year, it is literally EVERYWHERE. Those gangly, weedy looking circular blue flowered plants are chicory. To be 100% sure, do a google image search on "chicory", impossible to mistake.

I have only recently started using this herb, harvesting the roots locally. So I am no expert, but the research on the properties of chicory is solid, I would not omit or substitute it.

If you want to harvest it wild, bring along a good shovel, the taproot goes deep and is tough, you'll want to use something other than scissors for cutting off the top as well, something like tin snips.