How to Help Monarch Butterflies

The Monarch Migration

If you grow plentiful Ascelpias tuberosa—orange milkweed (also called butterfly weed)—then you may be blessed with plenty of monarch butterflies. These gorgeous orange and black pollinators will shelter in your garden for months, from March until October.

Then, the monarch butterflies migrate south every fall—the only butterflies to migrate as birds do! They’ll fly over 3,000 miles with the Sun as their guide, traveling about 50 miles a day. 

• The eastern population, which makes up the bulk of the monarch population in North America, travels from as far north as southern Canada down south to the border regions of Texas and Mexico, arriving at their roosting sites in November, where they’ll hibernate for the winter. 
• Some monarchs live west of the Rockies, who gather in southern California instead. 

Monarchs may take as many as five generations to complete a migration south! Monarchs normally produce four generations in one calendar year. Each generation goes through a life cycle of four stages: the egg, the larva (caterpillar), the pupa (chrysalis), and the adult butterfly. The four generations are actually four different butterflies going through these four stages during 1 year until it is time to start with stage one and generation one again. 

The 5 Monarch Generations

In February and March, monarchs come out of hibernation to find a mate. They then migrate north and east to find a place to lay their eggs.

This starts stage one and generation one. In March and April, the eggs are laid on milkweed plants. They hatch into baby caterpillars, also called larvae. It takes about 4 days for the eggs to hatch. Then, the baby caterpillar eats milkweed to grow. After about 2 weeks, the caterpillar will be fully grown and will find a place to attach itself to start the transformation process. It attaches itself to a stem or a leaf, and then, using silk, it spins and transforms into a chrysalis. Within the chrysalis, the old body parts of the caterpillar undergo metamorphosis to become a butterfly that will emerge in 10 days and fly away. It feeds on flowers and fruit in gardens for 2 to 6 weeks. This first-generation monarch butterfly will then die after laying eggs for generation number two.

The second generation of monarch butterflies is born in May and June, and then the third generation will be born in July and August. These monarch butterflies will go through exactly the same four-stage life cycle as the first generation did, dying 2 to 6 weeks after they become adult monarch butterflies. If the process starts early enough, there can even be a fourth generation in late August.

The final generation of monarch butterflies is different from the others. It’s born in September and October and goes through exactly the same process as the previous generations except for one part: The butterflies don’t die after 2 to 6 weeks. Instead, they migrate to warmer climates like Texas, Mexico, and California, where they hibernate for 6 to 8 months until it is time to start the whole process over again.

The Right Food for Monarchs

Monarchs must time their migration to coincide with milkweed growth. No milkweed means no monarchs!

• Monarch caterpillars eat only milkweed (Ascelpias tuberosa), which contains all the vitamins, minerals, and other nutrients needed to transform the larvae into butterflies.
• Adult butterflies also rely on milkweed as a nectar source, in addition to other backyard flowers.  

See our article, “Which Milkweed Varieties Are Best for Monarch Butterflies.”

Flowers for Monarchs

• To attract and help adult monarchs during their fall migration, plant milkweed, native flowers, and a few fruit-bearing trees. See the Almanac’s Growing Guide to Milkweed Plants.
• They also like to drink from mushy slices of banana, oranges, and watermelon.
• Plant other fall-blooming flowers that provide nectar, like asters and goldenrods; there are native species of each in almost all parts of the country.

Of course, avoid herbicides such as glyphosate and insecticides such as neonicotinoids, especially on fall-blooming plants.