En EspaŅol

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
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
Not Yet Rated

Wednesday - December 05, 2012

From: San Antonio, TX
Region: Southwest
Topic: Butterfly Gardens, Compost and Mulch
Title: Will recycled tire mulch harm butterfly larvae?
Answered by: Nan Hampton

QUESTION:

I discovered orange butterfly larva in the hardwood mulch under my Turk's Cap. Will it harm the larva if I switch over to recycled tire mulch?

ANSWER:

Mr. Smarty Plants is very happy that you are thinking about the potential effects of your choice of mulch material on insect residents of your garden.  Butterflies are beautiful and many other insects serve as pollinators in your garden.  However,  I am a little dubious that the larva you found in your mulch is a butterfly caterpillar.   Butterflies lay their eggs on the host plants that their caterpillars will eat.  The caterpillars are pretty much "eating machines" and munch away, growing until they have reached the size to pupate and form their chrysalis.  They don't really spend time in mulch unless they accidentally fall to the ground or have eaten up their host plant and are searching for another.  I suspect what you found in your mulch is the larva for a species of beetle.  Many beetle larvae overwinter in the soil.  Here are a few common species of mostly orange butterflies that you would find in Bexar County from the check list on the Butterflies and Moths of America webpage.  You can see their larvae on each species page:

Danaus plexipus (Monarch)

Danaus gilippus (Queen)

Agraulis vanillae (Gulf fritillary)

Dryas julia (Julia Heliconian)

Now, for the matter of using recycled tire mulch, there are several reasons NOT to use it for mulch in your garden.

  • From Environment and Human Health, Inc., the tire crumbs have been found to contain "volatile organic hydrocarbons (VOCs) with carcinogenic potential" that have been documented in human health effects "ranging from severe skin, eye and respiratory irritation to three forms of cancer".  These are released in gaseous form and also as leachates that can enter the ground water.
  • The tire crumbs are black and absorb heat from the sun.   You live in San Antonio where there is no lack of sun and heat in the summer.  Why put a mulch over the roots of your plants that will increase the heat of the soil surrounding them?
  • Whereas recycled tire mulch releases VOCs, organic mulches (e.g., bark, wood shavings, compost, etc.) eventually decompose and release compounds that provide nutrients to your plants, earthworms and beneficial soil organisms.

Aggie Horticulture has a very good article, Mulches for Enhanced, Low-cost, Low-maintenance Landscapes, that you might find helpful and you can also read an another excellent article, Mulches, from University of Missouri Extension.  You might also want to read RUBBER MULCH–Beware from Nature's Way Resources.

 

More Butterfly Gardens Questions

What would replace non-native orange tree leaves in butterfly hatchery?
July 17, 2009 - I have a very small orange tree that currently has dozens of caterpillars on it that look like bird droppings. I think I have narrowed them down to a swallowtail butterfly. I would love to let them ma...
view the full question and answer

Butterfly Plants for Chicago
September 13, 2014 - I live near Chicago, IL and am interested in planting a butterfly garden. Not sure when to start, but I want all native plants that would attract butterflies. Can you please let me know which plants ...
view the full question and answer

Butterfly gardening in Quitman, TX
February 11, 2009 - We want to establish a butterfly garden in our back yard. What plants should we establish to attract the butterfly for food and host planting?
view the full question and answer

Will Butterfly Plant Survive in Mansfield, Texas
January 06, 2012 - I have a butterfly plant that was very successful (about 4 feet tall) right up until the cold snap three weeks ago. I've read they have a tap root, so I'm hoping it will come back next spring. Mea...
view the full question and answer

Butterfly Garden, non-poisonous to Dogs, in Taylor MI
March 27, 2014 - I have a small fenced yard with a patio that my dogs have free access to. I would like to create a butterfly garden and add other plants that are non toxic to my dachshunds. Any suggestions. I am f...
view the full question and answer

Smarty Plants's Facebook profile 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.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center