Rent Shop Volunteer Join

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
Not Yet Rated

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

Where to find milkweeds and other butterfly favorites
March 07, 2016 - Our neighborhood in San Antonio is planning a big Arbor Day celebration. One of the events will focus on Monarch Butterflies. We will be releasing some live ones in our park and will have a booth th...
view the full question and answer

Creating a garden based on fragrance
May 04, 2012 - I would like to know which Fragrant Flowers are easy to grow and hearty for the climate i live in. Eastern part of washington state. Desert like in summer, warm summers.
view the full question and answer

Flowers that attract Queen butterflies
August 17, 2014 - Walking into the cloud of Queen butterflies around my Gregg's Mistflowers is one of the coolest things I've ever experienced, so I started wondering how I could prolong this "visitation". Can you...
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

Want to Amend Soil Without Harming Earthworms in Dallas Area
March 16, 2011 - I have a totally odd question. I live in the Dallas area in the blackland soil. I am removing sod from part of my back yard and will replant with nectar and host plants for butterflies. The soil is...
view the full question and answer

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