Poison hemlock (Conium maculatum) is one of the more common invasive plants in California. It resembles carrots and parsnips, but is toxic to all animals and humans.

It is a biennial plant that germinates throughout the year. In its first year it develops into a rosette. It does not flower until it is in its second year of growth.

What is Poison Hemlock?

Poison hemlock (Conium maculatum) is a biennial that takes two years to complete its life cycle. It is a highly toxic plant with a musty, unpleasant odor that comes from alkaloids.

This weed can grow two to ten feet tall and has ribbed, hollow stems with purple splotches. It produces small white flowers that are arranged in umbrella-shaped clusters at the end of the flower stalks.

When mature, the fruits are green and ribbed and contain seeds. The seeds are also poisonous.

It can be confused with other plants in the same family, including Queen Anne’s lace, cow parsnip, angelica, wild parsnip, fennel, and yarrow. The leaves and fruit of these plants can look like those of hemlock, too.

What is Queen Anne’s Lace?

Queen Anne’s Lace is a wildflower with delicate, lace-like flowers that can attract beneficial pollinators like bees and butterflies. It also provides natural color in a backyard garden.

It grows in dry, sunny areas, roadsides, disturbed sites, open fields and meadows, and woodland edges. It is often found near Common Chickweed, New England Aster, hawkweeds, and other similar plants.

In addition to its beautiful bloom, Queen Anne’s Lace has a long history of medicinal use. More than 2,000 years ago, Hippocrates prescribed crushed seeds to prevent pregnancies. Other medicinal uses of Queen Anne’s Lace include antiseptic, diuretic, and a remedy for bladder problems.

How to Identify Poison Hemlock

Poison hemlock is a member of the plant family Apiaceae, which also includes important crops like carrots, celery and parsnips. Its white umbel flowers (umbrella-like) resemble those of other white-flowered species in the carrot family, such as Queen Anne’s lace (Daucus carota).

The stems and stalks of poison hemlock are hairless and almost always have distinctive purplish red splotching or streaking towards the base of the plant. This splotching can help you distinguish it from wild carrot, which does not have this splotching on its stems and stalks.

Poison hemlock is a highly invasive weed that has spread across North America since its introduction as an ornamental plant in the 1800s. It has become a serious threat to livestock and humans due to its ability to release toxic alkaloids that can affect the respiratory, central nervous and reproductive systems.

How to Identify Queen Anne’s Lace

If you’re out for a walk and see long, thin stems and tiny white flowers that grow together in round bunches, they could be Queen Anne’s lace. Or they might be poison hemlock, an invasive species that spreads throughout the country and can cause serious health issues for humans.

But identifying these plants can be a challenge. They look so similar to each other that it can be difficult to tell the difference!

First, look at the flower head. It’ll be tightly packed with lots of tiny white flowers and a single dark red or purple one in the center.

Another distinguishing characteristic is that the young QAL flowers are flat umbels, and as they age and fruit develop, the flower folds inward into a bird’s nest shape. This is a rare feature among members of the carrot family and makes Queen Anne’s lace unique.