ragweed

You know that a plant must have some interesting qualities if it only grows in disturbed areas.  Such is the case with ragweed, a plant that connotes a drippy nose and runny eyes for many.

A wry sense of humor led to ragweed being given the generic name Ambrosia, meaning “food of the gods”.  Its rosinous leaves are regularly eaten only by insects, though horses and cows will consume them if other food is scarce.

Two species abound in south Louisiana.  Giant ragweed (Ambrosia trifida) may be l0 feet tall with large deeply lobed leaves.  Common, or dwarf, ragweed (A. artemisifolia) is shorter, usually four feet tall, and has delicately dissected leaves.  The flowers of both are in the junction between leaves and stems while the pollen is produced in upside-down cup-like structures lining the branches.  Ragweed pollen is distributed by the wind and is most responsible for allergies during the fall.

Ragweed is truly a pioneer species, normally being one of the first to invade barren soils.  It is a very important element in our ecosystem in that it produces nutrients that further enrich its soil, thus paving the way for the invasion of other species having different ecological requirements.  This phenomenon is known as plant succession.

Another curious characteristic accelerates the eventual disappearance of ragweed.  As they grow, some roots die as new ones develop.  These decaying roots release a toxin that is harmful only to ragweed.  When concentrations are high enough, the soil can no longer support these invaders and they die.  So, if you are allergic to ragweed pollen, have patience.  This, too, shall pass!

Most plants contain chemicals that are in some way harmful to humans and their pets, with symptoms ranging from mild nausea and dizziness to death.  The best rule-of-thumb for you and your children is not to eat or chew any parts or any plant species unless you are absolutely certain that it is harmless.  In case of emergency, call the Poison Control Center. 

Mushrooms are not included in this list since they are not plants.  Unless you are an expert, do not eat mushrooms.  Many are extremely dangerous and different people react differently to various forms.  If you want to learn more about them, LNC offers courses dealing with their identification and food value.

 ALL PARTS POISONOUS:  dieffenbachia, caladium, elephant ear, philodendron, autumn crocus, aconite, monkshood, foxglove, belladonna, laurels, rhododendrons, other azaleas, oaks, oleander, Jack-in-the-pulpit, skunk cabbage, jimsonweed, nightshades, horse nettles, water hemlock, poison hemlock, buttercups, elderberry (except ripe fruits and flowers), pokeweed (except young leaves), anemone, California poppy, amaryllis, blue bonnets, clematis, daffodil, delphinium, horsetail, hydrangea, jasmine, lillies, mimosa, mistletoe, night-blooming cereus, periwinkle, raintree, strawberry bush, yucca, ligustrum, Jerusalem cherry, moon flower.

BULBS, ROOTS, RHIZOMES, ETC.:  hyacinth, star of Bethlehem, iris, bleeding heart, mayapple, cyclamen, four o’clocks, spider lilly, Spanish bayonet, violets, tulips, death camas, pansies.

 LEAVES AND/OR BARK:  iris, Dutchman’s breeches, larkspur, lily-of-the valley, nicotiana, potato, Carolina and yellow jessamine, privet,daphne, English ivy, oleander, yew, black locust, buckeye, horse chestnut, wild black cherry, chokecherry, baneberry, mayapple, poinsettia, rhubarb, bleeding hearts, allamanda, boxwood, primrose, tomato, pomegranate, sweet pea, century plant, cherry laurel, lobelia, wandering Jew, Virginia creeper.

 FRUITS:  moonseed, mayapple (unripe), privet, poppies, mock orange, chinaberry, baneberry, holly, yaupon, lily-of-the-valley, daphne, English ivy, red sage, lantana, jasmine, yew, lobelia, sago palm, Chinese tallow.  

SEEDS:  camellia, loquat, tung tree, castor bean, rosary pea, larkspur, apples, black locust, buckeye, horse chestnut, jatropha, cherries, yew, wisteria (and pods), golden chain, cherry laurel, Chinaberry, morning glory.

PLANTS COMMONLY CAUSING DERMATITIS:  poison ivy (= poison oak), poison sumac, trumpet creeper, stinging nettle, eyebane, wild parsnip, Hercules club, Jack-in-the-pulpit,asparagus, marijuana, catalpa, virgins-bower, autumn crocus, poison hemlock, lily-of-the-valley, lady slippers, daphne, jimsonweed, wild carrot, larkspur, daisy fleabane, spurges, yellow jessamine, maidenhair tree, English ivy, spurge nettle, Juniper, wood nettle, lobelia, osage orange, oleander, mayapple, smartweed, some buttercups, rhubarb, curly dock.

 

REFERENCES

KINGSBURY, J. M.  1964.  Poisonous plants of the United States and Canada.  Prentice-Hall, Inc., Englewood Cliffs, NJ. 

KINGSBURY, J. M.  1965.  Deadly harvest:  a guide to common poisonous plants.  Holt, Reinhardt, and Winston, New York.

MUENSCHER, W. C. 1975 (rev.).  Poisonous plants of the United States.  Macmillan Books, New York.  277 pp.