Home > Great Big Greenhouse Blog > May 2013 > Allelopaths...


When I was researching Companion Plants, one of the things that fascinated me was reading about Allelopaths. These are plants that DON’T play nice with other plants. Scientifically, this seems to be a bit of a gray area. There apparently hasn’t been a lot of research done on which vegetables don’t get along with each other, so most of the information I found was on vegetable gardening websites like Mother Earth News.
A lot of people know that Black Walnut trees really want to be alone. Their roots actually secrete a chemical called juglone which can stunt the growth of or even kill certain other plants. Vegetable-wise, keep asparagus, blueberries, cabbages, tomatoes, peppers, eggplant and potatoes far, far away—60 to 80 feet away. There are plenty of other plants that also won’t thrive near Black Walnuts, so do your research. However, some vegetable plants aren’t bothered, so if you’re currently living with a Black Walnut tree, you can still grow beans, corn, carrots, onions, parsnips, squash, melons, and mint.
Another allelopath is the herb fennel. Fennel should also be grown by itself. It’s particularly toxic to beans and tomato family members. It’s also a prolific reseeder and in some states is considered invasive. For that reason alone, it’s probably best to keep it isolated—and cut off flowers before they go to seed.
There are other plants which are not considered allelopathic but that don’t get along with certain other plants. For example: legumes, like beans and peas, do not like onions, shallots, garlic or chives. Potatoes don’t like cucumbers, squash, pumpkins, tomatoes, sunflowers or turnips. Corn and tomatoes would rather stay away from each other and so would radishes and cabbage family members. Cabbage family members also don’t like tomatoes or pole beans.
Some of these pairings may not kill the plants involved, but may slow down their growth or impair their vigor. If you have ever had a vegetable or flower in your yard that just did not thrive and you were sure the light and conditions were right, then it might be possible that it just didn’t like its neighbors!
Posted: 5/6/2013 by Bonnie Pega | with 0 comment(s)
Filed under: BonniePega, Bonnie'sGarden
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