Variables:
ei0 = English Ivy (control)
ei1 = English Ivy (moisture 1)
ei2 = English Ivy (moisture 2)
vc0 = Virginia Creeper (control)
pg0 = Purple Giant Hyssop (control)
eivc1 = English Ivy (in the pot with English Ivy and Virginia Creeper combination)
eivc2 = Virginia Creeper (in the pot with English Ivy and Virginia Creeper combination)
eipg1 = English Ivy (in the pot with English Ivy and Purple Giant Hyssop combination)
eipg2 = Purple Giant Hyssop (in the pot with English Ivy and Purple Giant Hyssop combination)
eivcpg1 = English Ivy (in the pot with English Ivy, Virginia Creeper, Purple Giant Hyssop combination)
eivcpg2 = Virginia Creeper (in the pot with English Ivy, Virginia Creeper, Purple Giant Hyssop combination)
eivcpg3 = Purple Giant Hyssop (in the pot with English Ivy, Virginia Creeper, Purple Giant Hyssop combination)