Milkweed for Monarchs

On the move

It’s peak migration season in Texas.  Millions of monarchs have made their way along the Eastern United States, funneling into Texas, on the way to their winter site in central Mexico.  This migratory generation will be making stops all across the Houston area in search of food and shelter over the next few weeks.  Guided by an internal compass, monarchs are on a mission to reach their small mountain side retreat by early November.

Good news!

Researchers tracking the monarch population in Mexico recorded a 144% increase in numbers during the 2018-2019 wintering season. Many reports this year are already boasting record numbers, as well. Encouraging news, as monarchs have seen an overwhelming decline in the past two decades. Most information is recorded through citizen science efforts like Monarch Watch. Increased efforts to protect and restore habitats have played a large role in the population growth and offer simple ways for everyone to help.

For more information on the fall migration, be sure to read The Environmental Services Blog: ‘A Wonderous Journey’.

How to help

Cut back tropical milkweed

Tropical milkweed is a popular choice for many gardeners. With a long bloom season, adaptability to our region and availability in nurseries around town, it is an easy-to-maintain, monarch-friendly plant. This Mexican native can be a much-needed resource for monarchs to lay their eggs. However, there are also concerns with this plant.

Given the ability to grow year-round, tropical milkweed may interfere with the monarch migration causing more butterflies to linger later in the season when they should be on the way to their wintering sites. If butterflies delay travel plans for too long, they will run into temperatures too cold for them to survive. In addition to delaying monarchs late in the season, tropical milkweed may increase the risk of infecting monarchs with the OE protozoan pathogen. OE, ophryocystis elektroscirrha, is a protozoan parasite that is ingested by caterpillars.  The disease affects the development of a caterpillar during its transformation into an adult butterfly.  When adults emerge, they are often too weak to fly.  A mild winter without a freeze, results in tropical milkweed that is unlikely to die back. This allows infected plants to continue to grow and be available year-round for caterpillars to ingest; continuing the spread the OE parasite. The best thing for a strong migration and disease-free plants is to cut back your tropical milkweed and watch healthy monarchs continue south.

Cut back tropical milkweed plants to within four to six inches off the ground each October

Plant for spring. Plant natives.

If you don’t have milkweed in your garden, tropical or native, now is the time to plant for spring. Milkweed is the only plant that monarchs will lay eggs on and the only food source for their caterpillars. Monarch caterpillars can eat an entire plant in one day so be sure to plant at least 4-5 milkweed plants to provide adequate food next spring and summer. The Native Plant Society of Texas has a great article on native milkweed varieties for reference.

Not sure where to find native milkweed?  The Woodlands Township has milkweed seedlings to give away this fall.  In partnership with Nature’s Way Resources and the Heartwood Chapter of Master Naturalists, more than 13,000 milkweed seedlings were propagated over the summer.  Many residents, churches, schools and community organizations have already picked up milkweed to plant in gardens across the community.  If you are interested in receiving free milkweed, you are in luck.  4” pots of orange, common and green milkweed are still available at Nature’s Way Resources. These seedlings need to be planted by mid-November so be sure to pick some up before it’s too late!

In addition to planting milkweed, native nectar-rich plants are a much-needed food source for adult monarchs. Monarchs will travel North, through Texas from March to May looking for nutrients along the way. Planting in the fall allows native plants to establish a strong root system over winter, creating a more drought tolerant and robust plant for monarchs and other pollinators to visit the following year. 

Whatever plants you decide to add to your garden, be aware that insecticides and herbicides can be harmful to monarchs.  Plants can absorb chemicals providing leaves and nectar that is toxic to pollinators. Help protect monarchs and other pollinators by avoiding the use of chemicals in and around your garden.

For more information on Plant for Pollinators and the Milkweed for Monarchs programs, email enviro@thewoodlandstownship-tx.gov