ph: 361-935-1556
nancyk
July 30, 2021
by Virginia Ruschhaupt/Victoria County Master Gardener
Edited by Suzanne LaBrecque/Victoria County Master Gardener
(Last week's article in this two part series let you know which nectar plants are good in the butterfly garden. This week's article by Virginia Ruschhaupt is all about native Milkweeds, which are the host plants of Monarch butterflies and are great for growing in our gardens.)
PHOTO COURTESY OF GROW JOY - www.growjoy.com/store.pc
Swamp milkweed (A. incarnata), 4' tall, well-behaved, a favorite of the monarchs, requires moist soil.
PHOTO COURTESY OF GROW JOY - www.growjoy.com/store.pc
Butterfly milkweed (A. tuberosa), 3' tall, best choice if you are concerned about toxicity. It may be best to plant it without other milkweed varieties, since it's not the monarch's favorite when other choices are nearby.
A LOCAL PHOTO CONTRIBUTED BY HARLEN E. AND ALTUS ASCHEN
Zizotes (A. oenotheroides) has branches, stout stems, 1.5' tall.
PHOTO CONTRIBUTED BY VICTORIA COUNTY MASTER GARDENER VIRGINIA RUSCHHAUPT
The beloved tropical milkweed has lost favor. Due to a parasite that can over-winter on A. curassavica, it is best to remove tropical milkweed, or at least cut it down for the winter and several times during the year so it can make a 'clean' start.
PHOTO COURTESY OF TEXAS A&M AGRILIFE EXTENSION
Whorled leaf milkweed, including this Horsetail milkweed, is one of the more toxic milkweeds. The leaves grow in a whorl around the stem.
(https://rangeplants. tamu.edu/plant/horsetail-milkweed/)
LOCAL PHOTO CONTRIBUTED BY HARLEN E. AND ALTUS ASCHEN
Green Antelope Horns (A. viridis) 2' tall, grows in pastures and along roadsides throughout Texas.
LOCAL PHOTO CONTRIBUTED BY HARLEN E. AND ALTUS ASCHEN
Antelope Horns (A. asperula) with bluebonnets; 2-3' tall, prefers blackland prairies.
What’s special about milkweed? Milkweed (genus Asclepias) is the host plant, the only source of food, for the monarch caterpillar. If the monarch butterfly does not find milkweed, it will not lay any eggs, and there will be no more monarchs.
Milkweed is also the monarch’s source of protection from predators. After the caterpillar eats the toxic milkweed containing cardenolides, the monarch caterpillar and subsequent butterfly have a very repulsive taste. Many predators will not touch them after recognizing their color and pattern.
Likewise, milkweed is toxic to people, pets and livestock. Usually, only a small amount would be ingested due to the foul taste, but we need to take precautions. Toxicity level varies with different varieties of milkweed, as well as other factors.
Last Friday’s Gardeners’ Dirt column described how the shortage of native milkweed in Texas is a significant factor placing monarchs on the verge of extinction. There are more than 100 varieties of milkweed and 37 of them are native to Texas. Looking at the preferred ecosystem and characteristics of each, we can carefully select the best ones for the Golden Crescent area.
In order to attract monarchs to our gardens, planting at least 10 native milkweed plants is recommended, preferably two or more varieties. We can plant them in our pesticide-free nectar gardens, existing gardens or community gardens.
Good choices for the Golden Crescent area
Milkweed to avoid
This includes common milkweed (A. syriaca) whose invasiveness has given milkweed a bad name, plus green comet milkweed (A. viridiflora), broadleaf milkweed (A. latifolia), horsetail milkweed and others.
Although planting milkweed in areas grazed by livestock or baled for hay is not within the scope of this article, realize that milkweed with whorled leaves, such as horsetail milkweed (A. verticillata & subverticillata), may contain both neurotoxins and cardenolides, creating greater risks for livestock and poultry.
Butterfly weed (A. curassavica), native to Mexico, is the most often grown milkweed in the Victoria area. The monarchs love it, but it contributes to their decline. The problem with tropical milkweed is the presence of a protozoan parasite, Ophryocystis elektroscirrha (OE), whose primary host is the monarch butterfly. If the milkweed does not die back in a mild winter, the OE levels increase, affecting one monarch generation after another.
OE results in the butterfly’s inability to fully expand its wings when emerging from the chrysalis, rendering it unable to fly or with diminished capacity. It has also been debated whether evergreen milkweed might delay fall departure of the monarchs until it is too late. The recommendation is to get rid of tropical milkweed and substitute appropriate native milkweed.
Native milkweed plants are difficult to purchase except through native plant societies or master gardener sales. When buying milkweed, it is important to ascertain that neither the vendor, nor the grower used pesticides. A list of vendors for native milkweed seeds and instructions for successfully germinating and harvesting seeds can be found at vcmga.org/gardeners_dirt/2021_jul_30. (Scroll to end of page.)
Let’s get busy planting native milkweed, along with our nectar flowers, in our gardens and community gardens, so future generations can enjoy the monarchs.
The Gardeners’ Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas A&M AgriLife Extension – Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, TX 77901.
How to get Texas native milkweed seeds to germinate' Texas Butterfly Ranch - by Monika Maeckle
https://texasbutterflyranch.com/2013/03/13/how-to-get-texas-native-milkweed-seeds-to-germinate/
Harvesting seeds for yourself or to prevent milkweed from spreading where it is unwelcome - 'Managing Asclepias Plants: How to Control Spreading'
https://www.americanmeadows.com/blog/2016/10/25/controlling-asclepias-plants
Vendors for milkweed seed compiled by agencies involved in saving the monarchs (Verify with vendor to determine if seeds are native to your area):
1. https://xerces.org/pollinator-resource-center/south-central (native seed vendors for Texas and south central states)
2. https://www.xerces.org/milkweed/milkweed-seed-finder - enlarge the map at the bottom of the document to see vendors in Texas. Click the symbol on the map to get details for the vendor.
3. https://monarchwatch.org/milkweed/market/
4. Monarch Watch Milkweed Market Vendors - https://docs.google.com/spreadsheets/d/1qiqH5xOWKlZmid2sn0Lwjnqj77_EAoXyj4z8DcghMW0/edit#gid=1135739834 (native seed vendors for each state in U.S.)
Request free milkweed plants:
1. For schools and non-profits - https://biosurvey.ku.edu/application-free-milkweed-nonprofits-and-schools - (This is from Kansas, but is a national project)
2. For restoration projects (over 2 acres) - https://monarchwatch.org/bring-back-the-monarchs/milkweed/free-milkweeds-for-restoration-projects/
More pictures of milkweed in Victoria, Calhoun, and DeWitt Counties, by Harlen E. and Altus Aschen, local participants in MonarchWatch (tracking the monarchs)
ph: 361-935-1556
nancyk