Black Walnut trees and Sunflowers...killing other stuff

[Jeannine]

I read a very interesting article a couple of days ago which was discussing the problems folks have if they have Black Walnut trees on the garden, or even close by, they apparently give off a toxin called Juglone which contaminates the gound and kills off other plants, even the nuts falling on the ground can do it.

What was really interesting is that this can also happen with Sunflowers   in much the same way, they along with the Black Walnut are called allelopathic plants which simply means they  can react with others nearby and cause trouble, the dead opposite of companions planting as I see it. The black seeds from Sunflowers seem to be the worse. If planted in numbers they can kill off much of the plants round about especially apparently some types of grasses.

I have looked for a posting I read here recently about couchgrass(cannot find it)

In this posting someone said they had planted a whole lot of Sunflowers and the following season all the couch grass had died.

Someone else had  a similar experience with Jerusalem artichokes which are a member of the sunflower family.

I think this is very interesting and worth following on.

Have we stumbled on a couch grass cure???

Any comments anyone ??

XX Jeannine

[Jeannine]

[Baccy Man]

Allelopathic or phytotoxic plants also include broccoli, peas and sweet potatoes amongst other things but none of these seem to inhibit weed growth.

[amphibian]

Walnut are sometimes used in Italy to surround the boundary of an estate, effectively keeping unwanted plants from spreading inward.

[Jeannine]

Maybe the sunflowers are stronger than the other veggies you mentioned the stuff. I do know in Vancouver you are no longer allowed to plant Black walnut trees in a city as they can damage the surrounding homes plants.

XX Jeannine

[mc55]

the weeds are thriving underneath my sunflowers and three have been demolished by slugs  ::) maybe I should give them a stern talking to