Weeds are specialists. Having learned something in the battle for survival, they will survive under circumstances where our cultivated plants, softened through centuries of protection and breeding, cannot stand up against Nature’s caprices. Weeds, therefore, may be grouped according to their peculiarities. There are three major and several minor groups. The major groups are our main teachers, indicating through their mere presence and multiplication what is wrong.
The first major group comprises of weeds living on acid soil and indicating increasing acidity. To this group belong the Sorrels, Docks, Fingerleaf Weeds, Lady’s Thumb, and Horsetail on slightly acid soil.
The second major group indicates a crust formation and/or hard pan in the soil. Here belong the Field Mustard, the Horse Nettle, Penny Cress, Morning Glory, Quack Grass, the Camomiles, and Pineapple Weed.
The third major group consists of those weeds which follow human steps and cultivation, frequently spreading out with compost, manure, and wherever man “walks”. Here belong Lamb’s Quarters, Plantain, Chickweed, Buttercup, Dandelion, Nettle, Prostrate Knotweed, Prickly Lettuce, Field Speedwell, Rough Pigweed, Common Horehound, Celandine, Mallow, Carpetweed, and other similar plants, all too frequent companions of our gardens and yards.
Minor groups consist of those which show up here and there - they are not necessarily WEEDS - unless encouraged by man. They are, more-or-less, an extension of nature into the realm of man.