plants (in)compatibility

Most gardening books include advices on companion planting, i.e. positioning plants together that are reput- ed to have a beneficial effect on neighboring plants by discouraging pests and diseases or improving growth. I don’t recall a single warning on negative or at least unwonted effects of companion planting. And then surprise: this spring I’ve planted together cypress vine (Ipomoea Quamoclit pennata) and morning glory (Ipomoea purpurea), both annuals, and I’ve also planted two cypress vine seedlings to one bush of our perennial morning glory (Ipomoea indica). The idea was to mix the heavenly blue flowers of morning glory with the scarlet flowers of cypress vine. Well, through- out this spring and summer, not a single morning glory flower appeared on the bush accompanied by cypress vines (on the right) while unaccompanied bush (on the left) blossomed normally. Even more drastic difference is exposed by the two annual species potted together to climb over a metallic mash [ROLLOVER]: while both plants are reach in leaves (cypress vine leaves are deeply pinnatisect), only cypress vine flowers are present.

"The elder Geoffroy and Goethe propounded, at about the same time, their law of compensation or balance- ment of growth; or, as Goethe expressed it, ‘in order to spend on one side, nature is forced to economise on the other side’. I think this holds true to e certain extent with our domestic productions ... I suspect also, that some of the cases of compensation which have been advanced, and likewise some other facts, may be merged under a more general principle, namely, that natural selection is continually trying to economise every part of the organization ... Thus, as I believe, natural selection will tend in the long run to 

reduce any part of the organisation, as soon as it becomes, through changed habits, superfluous, without by any means causing some other part to be largely developed in a corresponding degree. And, conversely, that natural selection may perfectly well succeed in largely developing an organ without requiring as a necessary com- pensation the reduction of some adjoining part."

 2012-10-07 

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