Tansy Ragwort sounds like a Harry Potter character, but there’s nothing entertaining about this weed.  It’s an invasive, meaning it pushes out native plants, and also deadly.  All of the plant is dangerous.  It contains liver damaging alkaloids that are toxic to all animals but sheep (Sheep have ruminal microbes that can safely consume the ... Read More

This is a goathead, also called puncturevine.  It is also aptly named Terror of the Earth.  Stepping on a Lego during the night is nothing compared to getting one of these stuck in a toe.  Anyone walking a dog near a puncturevine patch will inevitably have to stop and remove a burr or two so ... Read More

St. John’s Wort has been used in humans as an *antidepressant (studies have been inconclusive), but there is no way a rancher would want this weed near his or her livestock. Besides pushing out native plants It is toxic to cattle, sheep, horses (there is conflicting information with goats—best to avoid), as well as dogs ... Read More

This thistle looks much like the other thistles.  It’s called the Canada thistle not because it originated in that country but that’s where it was introduced (scientists believe it was hiding in crop seed).    The thistle grows three to five feet tall with stickers and little purple heads (there are some white ones). The ... Read More

              Halogeton is both noxious and poisonous.  It pushes out native weeds through removing salt from the soil which is then leached back from the roots into the soil.  This both increases soil salinity and pushes out native weeds through the soil nutrient change.  The salt is a soluble ... Read More

Beautiful, isn’t it?  Like many invasive weeds, Pheasant’s eye began life in the U.S. as an ornamental plant and then spread into the wild. This weed is nasty.   It’s dangerous to horses and pigs, causing gastrointestinal disturbances and myocardial necrosis.  It likes to invade alfalfa crops and when it is dried is even more toxic ... Read More

Dalmatian toadflax was introduced in the U.S. for ornamental and medicinal purposes.  Quakers relied on the plant for liver and skin health.  Plants boiled in milk were set out in settlers’ homes to eradicate flies.  But as with most invasive plants, what began with the best of intentions got out of control.  The plant found a ... Read More

English Ivy, Hedera helix Atlantic Ivy, Hedera hibernica English Ivy is a plant that many people seem to like. This is really a plant they really ought to hate! While it is appreciated in landscaping as a dominant, evergreen groundcover and something you “don’t have to mow”, its ability to crowd out other plants is ... Read More

This is Yellow Starthistle, also known as golden star thistle, yellow cockspur, St. Barnaby’s thistle. At the stage in the photograph it resembles a dandelion. After it has bloomed it takes on the look of little cottonballs. It can grow from a few inches to 3 feet high. Some invasive species are unwanted because they ... Read More

A question that many who are not in agriculture might ask is “Why should I care about weeds?” The weeds featured in this column are called invasive for a reason. They take over a region, push out native grasses and steal water resources. Many livestock and wildlife will not eat them and will either starve ... Read More