I am hopeless at it, mostly because I never bring a guide with me and never bring the plant back. (Trees are easy, I’m contemplating all those herbaceous things!)
Still, there is some learning going on. Flat-topped goldenrod for example, has leaves that look more like a slightly overgrown tarragon than a goldenrod. The beautiful wild blue relative of our fall garden asters has smooth leaves that feel like kid leather; it looks very weedy indeed…until now, when its color has the cultivated varieties well and truly beat. Blue wood aster has slightly paler, yellow leaves than the more common white wood aster, and a more pronounced notch at the base. Grey goldenrod has leaves that look almost like a sage leaf, but without the pebbly texture. The calico asters, with their thousands of little flowers, are very stiff, with lots of little branches and leaves. One of the goldenrods that bloom all along the stems has a beautiful purple stem, the other doesn’t. The purple one has better form (and naturally is not growing in an area that is likely for long term survival: south of the barn where I must, must, do some weed whacking). And so forth. The goal, of course, is to be able to edit the meadow lawn areas correctly in the spring. For example, now that I know the difference between the flat-topped goldenrod and the regular goldenrod, I can remove the latter and keep the former in one area where the flat-topped type gives the right look. (besides being rarer) Thankfully, because I didn’t know what the weird tarragon like thing was this spring (though clearly Not tarragon) and did remember that it was where the flat-topped goldenrod had been I didn’t pull all of it…quite!
Some things are easy: yarrow, one of the black-eyed susans (the felt leaved one that blooms all summer and the deer Love, naturally)