Plants and other plants, their good & bad companions and worst weeds - being Volume 1 of ‘Plant Companions and Co-lives’
Gardeners have long observed some plants do better with certain plants nearby, and worse with others. Indeed with so many thousands of different plants in near infinite combinations it would seem most strange if none ever did interact in some way other than competing for the same resources.
All plants compete with their neighbors by abstracting air, light, water and nutrients more or less effectively from their shared environment. Companion planting is about how plants also gain advantage over their neighbors by adding substances into their environment. deliberately or inadvertently, altering their competitors performance.
To give our crops and flowers optimum conditions it is considered sensible to control weeds. Obviously it’s more effective to know and eliminate the more pernicious weeds than relatively benign ones. And now this must include other crops or flowers growing nearby that are acting much as extremely pernicious weeds.