The best thing to do, is not necessarily remove ur additional plants. First get a 55 gallon drum and fill-it 3/4 way with water, then add, 12 to 14 oz of vegetable oil, add: 1/2 gal. of vinegar, 12 oz of sugar, 4oz of baking powder, 12 oz of ammonia; mix thoroughly; then add 1 to 2 gals of sour milk to the mixture, let stand for right around an hour or so, (do not mix the milk into the other mixture, allow the milk to slowly mix itself, that way is will bind with the parts of the vinegar and not much more). After the mixture has set for an hour or more, you want to carefully pour 1/2 of the mixture directly at the base of the tree trunk, pouring the mixture so that it is even all around the diameter of the tree, its best to do this as the sun is setting. Wait 3 to 5 days then repeat the procedure with the remaining mixture. You will see results in right around 2 weeks, 3 at the very latest. Your tree will be fine, and so will the other plants.