Larkspur looks like a harmless cottage flower, with tall blue spikes that suit any garden border. Do not let the pretty bloom fool you. Every part of the plant is highly poisonous, from the roots to the seeds. The larkspur poisoning severity runs high. This flower ranks among the worst plant killers of cattle across the western United States. Gardeners grow both the annual larkspur and the taller perennial delphinium, and both carry the same poison. New growth and the seeds hold the strongest dose. If you grow larkspur at home or walk where the plant spreads on open range, the larkspur poisoning symptoms are worth knowing by heart.
The damage on grazing land is real. Cattle deaths from larkspur can reach as high as 15%, and the losses cost ranching communities millions of dollars each year. Green and colleagues published these figures in the journal Rangelands in 2020. Cattle find larkspur tasty and eat the most after the plant flowers. Sheep and horses take losses far less often, since cattle find the plant much more tempting. In a bad year, a single pasture can lose a large share of the herd. There is no proven cure once an animal swallows a heavy dose, so prevention beats treatment.
Larkspur threatens more than cattle. The plant is toxic to horses, dogs, and cats, though these animals seldom eat enough to die. The same poison hits a pet's nerves and muscles the same way. A person faces the same risk if any part reaches the mouth. That broad reach is a big part of what makes larkspur poisoning severity such a costly and stubborn problem. So you should keep children and pets away from the plant. Never add the blooms or seeds to food, tea, or a salad.
For a person, larkspur is dangerous to swallow in any amount. The first signs hit the mouth fast. Your lips and mouth start to burn, and your throat goes numb. Then the gut reacts hard, with intense vomiting and diarrhea. As the poison spreads, your muscles grow weak and start to spasm, and your pulse turns faint. In the worst cases the poison paralyzes the muscles you breathe with. That loss of breathing can be fatal. These larkspur poisoning symptoms can slide from mild to deadly within a few hours.
The poison works by blocking the signals between nerves and muscles. Your muscles cannot fire the way the brain commands. When that block reaches the muscles around the lungs, breathing stops. This is why a heavy dose can turn deadly so fast, in people and animals alike.
Timing changes the threat. Larkspur is most toxic during early spring growth, and the poison fades as summer moves on. The toxin can climb again in the flowers and the seed pods. So the plant stays risky through much of the season, well past one short window. Rain, cold fog, or snow can push cattle to eat even more. That shifting danger is a big part of how toxic larkspur is on grazing land. The pattern catches many ranchers off guard.
If you think a person or a pet has eaten any part of a larkspur, treat this as an emergency. Do not wait for symptoms to appear. For a person, call a doctor or your local poison control center at once. For a pet, call your vet or an animal poison hotline. Keep a piece of the plant to show the doctor or vet, so the source stays clear. Quick action gives the best odds, since the poison can act within hours.
Larkspur owes this danger to a group of alkaloids packed inside the plant. To learn which alkaloids do the damage and how the poison stops the muscles, read the FAQ on what makes larkspur toxic.
Read the full article: Larkspur Flower: Meaning, Growing, and Safety
