Monarchs on the Move

The annual migration of monarch butterflies occurs each year in the fall. No one knows for sure how millions of monarchs instinctively know when to depart and where to go. But it seems to be triggered by the autumn equinox and related to the Earth’s magnetic field.

Butterflies are important contributors to the world’s ecosystem. In fact, they not only pollinate flowers, but serve as a food source for birds, small animals, and other insects. The epic migration of monarchs is one reason they are so essential to the environment. These resilient insects travel all the way from Canada to Mexico across the United States each year, pollinating plants the entire way. They spend their winter hibernation in Mexico or Southern California.


Milkweed is a popular talking point for a lot of monarch enthusiasts and for good reason. Monarch caterpillars ONLY eat milkweed. It’s true that monarchs cannot survive without it. However, they are not reproducing right now and instead need energy from nectar plants for their enormous trip.

Additionally, O.E. (Ophryocystis elektroscirrha) is a parasite that infects butterflies that host on milkweed and it’s killing many monarchs. The epidemic has been made worse because some monarchs are not migrating and the infection spreads quickly in a static population. The lack of migration also increases inbreeding in the local monarch population. This weakens the butterflies and makes them more susceptible to other threats. For example, a butterfly fighting O.E. is much more susceptible to a small amount of insecticide in the environment.

Growing tropical milkweed at the wrong time of year can affect the monarch butterfly’s migration habits. It encourages the butterflies to remain in the south (i.e. Houston) and not migrate. This contributes to O.E. infection and their overall decline. While Tropical Milkweed (Ascelpias curavassica) remains an important food source for monarchs in the spring and summer, we strongly encourage butterfly enthusiasts to cut it back in October and continue to cut back new growth monthly until February. To learn more about O.E. and Tropical Milkweed, click here

How You Can Help

As monarchs migrate, they need water, ample nectar sources, trees or other protection at night for roosting, and connected habitats. Studies have shown that monarch numbers decline significantly as they get closer to their destination in Mexico. Since Texas is in the last leg of their route, it’s even more important we provide them with nourishment to survive. We have a unique opportunity to help monarchs fuel up with nectar as they continue on their journey.

To learn more about creating an official monarch waystation, visit To catch a glimpse of these beautiful pollinators, you can plant flowers now to attract them to your yard. Warren’s has an excellent selection of coneflowers, Zinnia, Lantana, and more in stock now as well as a wonderful selection of Native American Seed. We even have some great combinations of these pollinator plants grouped together in ready-to-go containers. Stop by the Garden Center so we can help you select the best plants for your yard and these special creatures.

Monarch Migration Map

Monarch Migration Map