Who said Plants don't bite each other

As a passionate gardener my hobby is to watch garden plants. Last year we planted Cucumber, Ridge gourd and pumpkin together(Just 2 feet apart from each other). When I planted them I thought they will not come on each others way. But the fact is just the reverse. Pumpkin over grew other two and suppressed ridge gourd only partially and cucumber completely. Then I thought Cucumber is a docile plant and needs to be grown separately while Pumpkin and ridge gourd can be grown together.

This year, I planted cucumber, Bitter gourd and snake gourd together assuming that all of them are peace loving plants. What I see now is just so surprising. Cucumber now overtakes other two plants. What is amazing is, whenever the other two plants are trying to climb the support provided to them, cucumber successfully pulls them back putting the tendril around the apical part of the other 2 plants. It is not putting the tendril around the creeping low lying parts of the other 2 but only the branch that is climbing. I am not sure how it notices that this is the apical portion of the plant and found a support, so pull it back!!! I did not see the same tendency with other 2 plants however. They are just trying to escape rather than fighting back with cucumber. So, is there something called as relative aggressive - sism in plants? So I would scale the aggressive nature of the plants in the following order:

Pumpkin > ridge gourd > cucumber > Bitter gourd and snake gourd (Sorry I am yet to notice the relative aggressive sism with bitter gourd and snake gourd).

Another thing I have noticed is towards the side where the cucumber plant is in active aggression with the other 2 plants, there are full of small fruits, where as the other side although very healthy, has not got even a single fruit. Is it that Cucumber feels extremely threatened by the other two, so procreates faster? If somebody can answer how plants sense this types of things and how send messages to different parts of their body and which part of the plant acts as the decision maker will be really amazing.

Thanks for reading the article.