Host an Event Volunteer Join Tickets

Support the plant database you love!

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Tuesday - May 06, 2014

From: Comox, BC
Region: Select Region
Topic: Poisonous Plants, Wildflowers
Title: Is Fern-like Plant with White Flower Poison Hemlock?
Answered by: Anne Van Nest

QUESTION:

I have a fern-like plant which produces white flowers that uncurl from the stem as the plant starts to grow. Is this poison hemlock?

ANSWER:

Poison hemlock (Conium maculatum) is not a North American native plant (it is from Europe, North Africa and West Asia) but is a very noxious plant found naturalized along many roadsides or open fields in Asia, North America, Australia and New Zealand. It is not related to the native tree called hemlock (Tsuga canadensis). Poison hemlock is a member of the parsley family and has similarities to Queen Anne's lace (Daucus carota) and American wild carrot (Daucus pusillus). It can grow very tall (to 8 ft) - especially if moist. The plant has hollow stocks with large umbel-shaped flower clusters. Poison hemlock flowers in late spring (while wild carrot blooms later in summer).  Poison hemlock is toxic to animals and humans with symptoms appearing within three hours of ingestion. All parts are poisonous (even the brown, dead stems for years afterward). Avoid eating the plant or getting the plant sap on your skin. Symptoms are serious and sometimes deadly. Immediate medical attention should be given as the poison is fast acting. Approach it with extreme caution.

To see pictures of the plant at different life stages of poison hemlock visit the King County Noxious Weeds webpage for Poison-Hemlock. There are many look alikes including giant hogweed (Heracleum mantegazzianum), cow parsnip (Heracleum maximum), purple-stemmed angelica (Angelica atropurpurea), spotted water hemlock (Cicuta maculata), and wild parsnip (Pastinaca sativa). A good reference to see the various similar looking plants is Giant Hogweed and Look-a-Likes.

 

From the Image Gallery


Purplestem angelica
Angelica atropurpurea

Common cowparsnip
Heracleum maximum

Common cowparsnip
Heracleum maximum

Common cowparsnip
Heracleum maximum

American wild carrot
Daucus pusillus

American wild carrot
Daucus pusillus

American wild carrot
Daucus pusillus

More Poisonous Plants Questions

Eliminating silverleaf nightshade from Albuquerque NM
June 07, 2014 - I have silverleaf nightshade in my yard and would like to eradicate it (yeah, I know, good luck!) or at least control it. Do you have any suggestions?
view the full question and answer

Information on Royal Empress tree
May 01, 2008 - Would like to have some information on the royal empress tree; it is a non-native tree.
view the full question and answer

Planting Mountain Laurel grown from seeds in Argentina
April 09, 2014 - Hello, I was transferred to Cordoba, Argentina 2 years ago from San Antonio, the climate hereis similar to S. TX, anyway I brought some mountain laurel seeds with me and they have been in 2 gallon pot...
view the full question and answer

Identification of potentially toxic weed in California
May 08, 2015 - Hi! Sorry about the error, I'm not very computer savvy! I have a weed that grows on my land; about 1 foot tall its flower looks like a Q-tip. My neighbor says it killed her horse! I can't find i...
view the full question and answer

Non-native astilbe resemblance to non-native poisonous castor bean from Tomslake BC
May 21, 2014 - I have a plant that looks like a castor bean but it has flowers like a Younique Silvery Pink Astilbe. Need to id because castor bean is poisonous. This plant grows up to 5 feet in height. Thank you !
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.