What Landscape Plants are Poisonous to Cattle?

The pastoral beauty of a farm or a rural home draws on the close cohabitation of livestock and useful and beautiful plants. However, if cattle graze close to your garden, make sure that your selection of plantings doesn't expose them to dangerous toxins. Many ornamental plants, both wild and cultivated, can cause cows serious illness or death if ingested.

Valued for its cheery yellow blossoms, the buttercup can kill or severely damage cattle that eat its stems or leaves. It produces an oil called protoaemonin that irritates cattle's mouths and digestive tracts. Affected cattle will produce bitter, red milk. If the buttercup plants are dried up, they will not affect cattle. Some buttercup varieties are more potent than others.

A popular tree for landscaping, the oak's acorns or young buds can harm cattle, as well as horses, sheep and goats, if ingested. Symptoms include frequent urination, a dried muzzle area, constipation, extreme thirst and a roughly textured coat. The oak contains toxic pyrogallol, an acid, which damages the kidney. The oak is not consistently hazardous; many cattle can ingest acorns without any harm. If cattle show symptoms of oak poisoning, feed them 3 lbs. of a feed mix with 10 percent slake lime, a highly alkaline substance.

Foxglove's purple flowered turrets make it a classic addition to the English garden. However, the plant can be highly toxic to a range of livestock, including cattle. Eating any part of the plant, at any stage of its growth, will expose an animal to digitoxins and cardiac glycosides, potentially fatal poisons. Common symptoms include dizziness, vomiting, irregular heartbeat, delirium, convulsions and sudden death. During its first year of growth, foxglove is easily confused with comfrey, an edible herb.

Larkspur, a perennial with showy blue-purple flowers, is toxic to many kinds of livestock, though particularly to cattle. It contains delphinine alkaloids and cardiac glycosides throughout all of the plant's parts, with the highest concentrations in the seeds and new growth. Symptoms of larkspur poisoning include nervousness, weakness, salivation, bloating, nausea and a rapid heart rate. It can be fatal to cattle, lethal when consumed in excess of .7 percent of body weight within an hour.

The black cherry contains a glycoside called prussic acid, which is a form of cyanide. This toxin can poison cattle or other livestock. Wilted leaves or fallen autumn leaves contain the highest concentration of poison. The ground cherry also contains toxins among its fruits and leaves, especially before they ripen.