Explore Plants
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.
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
rate this answer
Tuesday - November 01, 2011
From: Austin, TX
Region: Southwest
Topic: Butterfly Gardens, Poisonous Plants
Title: How toxic are milkweed (Asclepias spp.)?
Answered by: Nan Hampton
QUESTION:
We are considering a monarch waystation for our local elementary and are concerned about milkweed toxicity. Would it be safe to plant it in reach of children?ANSWER:
The Poisonous Plants of North Carolina database says that all parts of Asclepias species are poisonous, but are "Toxic only if large quantities are eaten." The Toxic Plant Database of Purdue University Veterinary School agrees with this assessment. Moreover, the plants are generally unpalatable. Grazing animals don't readily eat them unless they are confined in a pasture with large numbers of plants or the plants have been included in hay given to them. The compounds that are toxic in the milkweeds are cardiac glycosides. The monarch larvae eating the plants sequester these toxins in their exoskeletons where they remain even after they metamorphose into butterflies. Not only do they make the butterflies taste bad, but the glycosides have an emetic effect that causes a predator, such as a bird, to vomit. Predators apparently remember and associate the butterflies with the unpleasant taste and learn to avoid eating the monarch.
According to the Botanical Dermatology Database, several species of the family [e.g., Asclepias viridis (Green antelopehorn)] can cause dermatitis from the milky sap so you should probably protect the plants to keep them from being broken and exuding the sap.
Since milkweeds are unpalatable and they don't contain attractive fruits that might tempt the children to eat them, I don't think that you should be overly concerned about including them in your butterfly garden.
More Butterfly Gardens Questions
Soil improvement near Kerrville, TX
December 11, 2010 - We live in the Kerrville area; the soil is extremely shallow and deficient. The yard consists of mainly native plants, with a concentration of plants for butterflies and birds. What kind of soil and ...
view the full question and answer
Deadheading flowers on hybrid Black Knight butterfly bush
July 17, 2008 - I have two Black Knight Butterfly bushes in my landscape. Should I deadhead the flowers on this bush? Also, should I prune this back, if so, when, how much? I live near Kansas City, Missouri.
view the full question and answer
Butterfly/hummingbird garden plants for Hill Country, TX
February 04, 2011 - What drought resistant plants would you recommend for a Hill Country butterfly/hummingbird garden that receives at least a half day of sun? It has afternoon exposure.
view the full question and answer
Native plants for butterfly garden in Waco, TX
February 03, 2008 - Few weeks ago I sent you a letter but never got an answer back.
I would like to have your suggestions of native plants for a butterfly garden (30'x 30') here in Waco. The plants must be (1)drought ...
view the full question and answer
Shrubby options for a bird lover in New Jersey
September 07, 2011 - Could you please recommend a native shrub to NJ that grows to about 3-4 feet, is very low maintenance, does well in afternoon sun and is also something the birds will like? Thank you.
view the full question and answer
 |
Support the Wildflower Center by Donating Online or Becoming a Member today. Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends. |
