No but seriously, those wild-growing surprise plants are one-in-a-thousand super selected champions of evolution, like those concentration camp survivor Jews who lived to over 100 after the war. The ordinary simply die, only the best survive. Modern commercial high-yield crop varieties often need optimal conditions to thrive and are not resilient to stress at all. Also they're clones with no variation so natural selection doesn't work.
Bottom line, plants most likely don't turm brown from your malicious bear aura alone, there must be some physical cause and we gotta find out what you are doing wrong. But it may very well be that the varieties you tried to grow are simply unsuitable for your location. It's always easier to adapt crops to your environment than your environment to the crops you'd like to grow. Host learned that the hard way because he's a fool.
