Alfalfa is a popular commercial legume forage plant which is dried into alfalfa hay for horses, cattle and other livestock.  It is well documented that the mature (1 year old +) plant produces a toxin known as ‘medicarpin’ which damages newly sown seed and those plants which do manage to germinate from it.  This is known as ‘autotoxicity’ because the plant is toxic to itself.

Farmers are advised to cut and remove the top growth before ploughing to destroy the roots of the alfalfa but the chemicals released remain in the soil and rain will wash surface chemicals into the root zone.  The recommendation for farmers is to grow cereals or other crops in the soil before trying to seed again with alfalfa.

Source http://www.omafra.gov.on.ca/english/crops/field/autotox.htm

There are a number of plants which release chemicals toxic to other plants. The process of releasing chemicals that either benefit or harm other plants is allelopathic, but most of the plants which are allelopathic are harmful to other plants which is why the term has become almost synonymous with the term ‘killer plants’, or ‘natural herbicides’.

Fennel, a great herb for digestion, has an adverse effect on most other plants except dill, with which it may cross polinate so best not to grow the two together. In turn wormwood has a detrimental effect on fennel.

Black walnut releases a chemical called juglone which affects a number of plants and it is interesting to see that all three are common ingredients in herbal remedies for internal parasites.

Fennel and wormwood are natural flea repellents, and fennel is attractive to beneficial insects and birds, but keep them in their place.

Those of you interested in the role of rabbits and hares in literature could do worse than start off with Terri Windling’s article on The Symbolism of Rabbits & Hares.

The article on the website The Journal of Mythic Arts is beautifully illustrated, including pictures by the author as seen above,  runs over four pages and has links to rabbit books on Amazon for those looking to buy a book on rabbit tales.

The article contains links to the Three Hares Project, researching and documenting an ancient symbol where three hares, running in a circle, each appear to have two ears when closer examination shows they in fact have only one ear each.