In article ,
Frank Martin wrote:
Are some plants better planted in a group of their fellows than just singly?
My grandmother says some plants are like flocks of birds and do better in a
group. Does anyone know about this?

Some plants do better if not planted in isolation because a group may e.g.
shade each others roots or provide a cooler or more humid microclimate
under a canopy of leaves of adjacent plants. While this wouldn't require
the plants to be all of the same species, if they are the same, competition
will be more evenly spread out so the "weed-choked" appearance will be
minimized.

As an example, a friend tells me she can't grow tomatoes in the extreme
summer heat in the central valley of California - she buys them from the
farmer's market. So how do the farmers manage? The air under the canopy
in a large field of tomatoes gets cool enough at night that pollination
can occur. A few plants in a garden don't have that advantage, and fruit
never sets.

That said, your grandmother may be on to something. The field of chemical
communication between plants is a new one, and there may be some surprising
interactions. Which species has she observed to do better in groups?