The Weed That Killed California Interesting features of the common St. John's-wort are its unusually shaped and marked petals along with its many long, flashy stamens. There is an alien weed that now sports unusually bright rich yellow petals, adds brilliant contrast to the whites and blues of other roadside plants, and which at one time was considered the leading economic loss to California – the common St. Johns-wort. An estimated two million acres in that state had been overrun by this extremely successful plant by 1950. Not only were the loss of pasture land and range land enormous financial setbacks, but stock fatalities also were very severe. This plant is one of many denizens of poor and mediocre soils that are typical of dry pastures, roadside ditches and neglected fields. The plant is native to all of Europe, North Africa and Asia except the Arctic regions. It is listed as a bad weed in 21 countries. The sap of all parts of the plant contain sour blistering juice and, as a result, cattle and even most insects avoid it. White cattle especially, along with some white goats and sheep, eat the plant and the juice goes through their digestive system, then travels to the skin resulting in blistering and a loss of hair. The photosensitizing action of the plant is due to two fluorescent substances, hypericin and hypericum red. The typical cow or horse having pigmented skin is not affected whatsoever. By the way, some humans can experience the same skin reaction when using herbal remedies containing hypericin. Apparently most people simply handling the plant may not be affected by the juice unless they are extremely sensitive to sunburn. John Gerard, 1633, notable herbalist, had entirely different beliefs about this plant. He wrote: "The leaves laid upon broken shins and scabbed legs heal them, and many other hurts and griefs, where it took its name Tout-saine, or Tutsane, of healing all things." Other photosensitizing plants known to cause skin problems on some people include Queen Anne’s lace, wild parsnip (a very bad plant to handle!), some meadow grasses and various species of buttercups. Aside from the potentially bad properties of the plant, common St. Johns-wort has many interesting qualities as well as fascinating history and folklore. Its scientific genus name is Hypericum (hy-PEAR-i-cum) the ancient Greek name of the plant. It is possibly from the god Hyperion who, in Greek mythology, was father of the sun god, Helios. Dating back many centuries, a common belief was that the plant first bloomed on St. John’s Eve, June 24. Here in northeast Wisconsin you can expect to see these brilliant yellow weedy flowers begin blooming around the time of the summer solstice, about June 22. Years ago, in pre-Christian times, the farmers paid close attention to the position of the sun in the sky and did their planting accordingly. How natural it was to take note of what is now called the St. Johns-wort, attractive and eye-catching, when this important season arrived. In later years this celebration of the summer solstice became associated with St. John the Baptist whose date of birth was thought to have coincided with the summer solstice. So today we have the St. Johns-wort, interpreted to mean "St. Johns plant," the suffix "wort" referring to "plant." There is one interesting feature of the leaves of all plants in this genus. Hold a leaf up to the bright sky and you will easily see what appear to be many tiny translucent pinhole-size dots on its surface. These dots are lighted by the sun and in effect become little windows. A simple hand lens will greatly enhance your view of this phenomenon. The plant’s species name, perforatum (per-fo-RAY-tum) is related to these tiny windows. Take a close look at the unusually-shaped yellow-orange petals, five on each blossom, and you will notice that they are rounded on one side and rather straight on the other. The petals are frequently black-dotted on the margins of their rounded sides. The common St. Johns-wort is in flower from mid-summer to fall, one of the longer blooming seasons of weeds. These flowers of such beautiful symmetry have no nectar but naturally do produce pollen. The many long, flashy, outward-flaring stamens are formed into groups of three. Female parts, the pistils, are long and thin and stand taller than do the male parts, the stamens. There are three on each blossom. It is quite natural that visiting bees, for example, will immediately come into contact with the longer pistils and their sticky stigmas at the tips, transfer pollen picked up at a previously visited flower and bring about very efficient cross-fertilization. Here is an interesting bit of folklore, true or untrue, that I picked up from a fellow naturalist. Remove a small unopened flower bud from the St. Johns-wort and firmly squeeze it from the bottom upward toward its tip. You will notice that a dark red juice oozes from the damaged bud. Story has it that a lady insisted that St. John be beheaded. Please don’t ask me why! Naturally the red juice appearing from the tip of the ruptured flower bud symbolizes the blood of St. John! Included in the belief is that seeing this red sap will be experienced only by females. (All you inquisitive men -- go ahead and try it!) Agriculturists soon learn that St. Johns-wort, being an extremely persistent plant that produces thousands of seeds, can be very difficult to eradicate. Being a regular "Jekyll and Hyde" of the weed world, this brilliant summer plant has its good points along with the bad. This column appeared in the Door County Advocate on 08/07/2004. © Copyright 2004 Roy Lukes. All rights reserved.