Well I was wondering if there were any good poison recipes/plants anyone knows of. I am especially looking for a primitive kind, like I could simply find a plant and make the poison. Preferably a plant that grows in the NE U.S. area, maybe common. I have holly, and I know that it is poisonous, at least if it is eaten, and I have stinging nettle, so they may give you ideas. Thanks in advance  Oh and don't worry I'm not planning to kill anyone with them! 

Hmm, interesting....... [ Evil laugh ]

I dont think that would kill in 5 minutes. Might eventually give them gangrene and they die, but not 5 min. Use deadly nightshade berries, preferably purple, for killing stuff. Dont know what you want to kill, but whatever

Hi,
Morning glory although it causes hallucinations, is not strong enough in any part of the plant to make a blade poison. I'm quite sure of this because I grow and use these seeds myself.
Coating your blade with piss and poopy would work to cause infection but I have high doubts about 3 or 5 minute kills. But it does work. It was a common tactic of the Viet Cong to coat punji stakes like this.
I have read a couple of times that the sap of the Yew tree is quite poisonous and it is believed that it was used to coat arrow heads in medieval times. It might be worth looking into but I'm not sure if the Yew grows in North America.
Another possibility would be wolfsbane. This is highly poisonous, only 1/15 of a gram of leaf material ingested can cause death in an adult. Mixing the crushed seeds (these often have the highest concentrations of chemicals in a plant) with fat should provide an adequate medium for coating a blade with poison. You could also try looking at Monkshood, hemlock or the various datura species.

There are tons of poisonous plants in the NE. I do classes on plant uses. Just a few are
Baneberry
Wild Hydrangea ( the worst)
  Hellebore
  Nightshade
  jimsonweed
  Fly Agaric mushroom
  Shaggy mane mushroom, when combined with alcohol- my prefered way of poisoning someone
   Hoarse chestnut
heheheh

Im familiar with fly agaric, Ive eaten them a few times. Your tale of the vikings using them is interesting and I havent heard it before. In Siberia it was the complete opposite. The rich people would eat the mushroom while the peasants would wait for them to piss and drink that. The reason for this is that the active chemicals are not broken down by the body. In fact you can even drink the piss off someone who has drunk the piss and it will still work.
I'm not sure about the berserks using fly agaric in battle. Working out a correct dosage with them is difficult as the strengh of one mushroom to the next can be quite different. This can lead to hardly noticable effects to a complete divorce of mind and body, just what you dont need in a fight. They could have used alcohol of course, or another suggestion is one of the milder datura related plants like Henbane. Up until the middleages pilz beer used to be brewed with Henbane leaf.
But the nearest example we have to the berserks were the Amoks, who also worked themselves into a battle frenze, but because they were muslims did not ingest any drugs or alcohol.
The Amoks were so vicious that US Officers facing them asked for the caliber of their revolvers to be increased because 6 shots with their old revolvers (sorry cant remember the exact caliber) sometimes would not stop a man in battlefrenzie.

Ooh lots of replies. Thank you everyone.
Kold, peach pits eh? I have a lot of those. I'll research and find out more.
Then, I'll have to try that strong poop and urine mixture. It could be a could blowgun poison if it works that fast.

Aconite tubers and leaves are frequently of very poor quality, and with foreign admixture as found in market, having been gathered without regard to season, species, or quality, by the poor peasants while engaged in watching the grazing herds. The shrivelled and decaying growth of the previous year is, as compared with the recent growth, relatively feebler. The aconites were well known to the ancient Greeks, Romans, and Chinese. It provided certain native tribes of the East with an active arrow poison. The root should be collected in winter or early spring; the leaves just before the blossoming period, or when the plant has but partially bloomed. The virtues of aconite remain intact upon drying, the whole plant being acrid and fully yielding its medicinal properties to alcohol. Various other plant species are present as admixtures, and especially, according to Holmes (Pharm. Jour., 1877), are substituted the roots of the Imperatoria Ostruthium, Linné. (European masterwort). As the latter tuber is aromatic, its detection is not difficult, though the roots somewhat resemble the aconite tubers. Good aconite is usually known by its characteristic benumbing taste. Aconite was introduced into modern medicine by Baron Störck, of Vienna, about 1762.
more info at:
http://www.ibiblio.org/herbmed/eclectic/kings/aconitum-nape.html