On the paper wasp nest. if you can get out there at night, harbor freight makes these little grabbie fingery things for picking up trash. Go out at night and snag the nest down. They WILL be pissed obviously, but catching them when they are sleeping might help.
Another way, although geeky and probably not for most people. I have an adjustable 10 watt laser. I will aim at a nest and burn them to the ground, and stomp on them. You can kind of pick them off one at a time that way. Natural, no chemicals and if you don't absolutely smoosh them, you can use tongs mentioned above throw them in a dish and feed them to the birds after you killed them off.
Another way, if you MUST be chemical free, one of these extension reacher grabby things, they make pressure sprayer 'arms' that will extend 15 feet or so with the hose to douche the side of your house or whatever, zip tie a vaccuum hose to that and vac them up. Then deal with what you got in the vac. (this is VERY dangerous, which is why I will NEVER recommend this route until you have been thouroughly TRAINED in the whole 'wasp thing'.) You can get rid of them that way.
if you got an arm, steel is strong, paper nests are not, prop the arm up next to the wasp nest with an M-80 or other similar 'thing' in it, use the laser to light it,'s fuse, kaboom, nest gone, steel arm and holder, unharmed.
There are many ways but for safety reasons if you do not want to use, touch and die method of chemicals.
I just re read your posting. Ok this is on plants...
Get a clean mayonaise or something else jar, go out at night, might want to use two people, one to hold a flash light the other the tool. Take a mayonaise or similar jar, something STURDY, slowly work your way to the nest, jar on one end, lid on the other, quickly bring them together, pinching the nest IN the jar, between lid and jar, close lid tightly on jar and PULL, this way the lid / jar is grabbing the nest which is inside, and when you pull back it's stem breaks off and it falls INTO the jar, with the wasps, you already have it pretty much closed, just finish aligning the lid, twist it close, then leave nest and all in the sun for a day closed up. Lack of O2 and heat should kill off already alive wasps, heat nukes the nest. Shake it VERY hard to flap and bang that nest around inside that jar, to percussion injure / kill anything that might be left, and then when you dont see stuff moving around, open dump in toilet and flush.
id say feed to chickens but they are stupid animals and that would be the ONE time they run AWAY from you when offering food, leaving you in a bad spot
Aaron
Edit: if its light enough out and they find you while raping their nest, you are in a bit of a problem, but otherwise, wearing long sleeves, gloves , even a pull down ski mask / hoodie, depending on your situation might help a bit too, if they are taking flight, all that might give you enough time to mash one before it lands or does it's drive by and stings you but BEWARE if you Do kill one by smashing it, it will release phenomes which pretty much WILL signal to the rest to attack this thing and kill it..... that thing is you,... if you mash one, it is probably in your best interests at that point to retreat quickly and remove item of clothing you mashed it into.