Monarch butterflies are majestic, indeed. Unfortunately, loss of habitat and food has caused their numbers to decrease over the years. To increase their numbers, many gardeners are helping out by planting milkweed, the only food source for monarch caterpillars. Planting milkweed is also the best way to get a front row seat to the action! Watching monarchs grow and transition from egg to adult is a treat.


Monarch egg in the Tonkadale Greenhouse Monarch ZoneMonarch females lay eggs on the underside of milkweed (Asclepias) leaves. This is the only plant they will lay eggs on because the leaves of milkweed are the only thing Monarch caterpillars eat. The eggs are tiny, and are a pearly greenish or off-white in color. Usually there will be only one egg per leaf, and it may hatch as early as three days or as late as a week. Once hatched, the tiny caterpillar (they are so small they could fit on a pencil eraser) eats it’s egg shell!

Tonkadale Greenhouse employees regularly check our milkweed plants for monarch eggs and caterpillars and move them into our custom-built butterfly enclosure, which is viewable to the public in the perennial section.


Caterpillars in the Tonkadale Greenhouse Monarch ZoneThese kids grow quick! They eat so much, and so fast, that they grow tremendously quickly. As they do, they molt (or shed their skin). The stages in between molting are called instars, and they will go through five stages of caterpillar (also called larva) growth, all within 10-14 days. Along with eating the leaves of milkweed during this time, they will also eat their shed skin for nutrition.

Our resident monarch specialist, “Butterfly” Bill Porter, keeps the caterpillars we find well-fed with home-grown milkweed.


Caterpillar in J formation in the Tonkadale Greenhouse Monarch ZoneOnce the caterpillar is ready to start the transition into a butterfly, it will attach itself to underside of a leaf or structure, or even a blade of grass. It moves off the milkweed it’s been feeding on, so if you’ve been watching a caterpillar on milkweed and it’s suddenly gone, carefully look around at the other plants nearby.

The larva attaches itself by way of a little thread of silk, and forms a “J” with its body. It remains in “J” formation for about a day. The next step it will take is to begin splitting it’s skin from the back of it’s head (so to speak) to reveal the casing known as the chrysalis. This is an incredibly interesting process to watch.

Single chrysalis in the Tonkadale Greenhouse Monarch ZoneThere is all sorts of wiggling and wriggling going on at this time, including even after the chrysalis is formed.

What’s up with those gold-like dots that are so pretty? No one is quite sure what their function is, or if they are just a by-product – isn’t nature fascinating?

Chrysalises in the Tonkadale Greenhouse Monarch ZoneThis chrysalis stage lasts 10-14 days. As the end of this stage nears, the chrysalis turns from green to a translucent black, and the wings of the butterfly can be seen through it.

Emerging butterfly

Emerging butterly in the Tonkadale Greenhouse Monarch ZoneThis happens quick. In just a few seconds, the monarch splits the chrysalis open (sometimes you might even hear it crack!) and the butterfly almost spills out, hanging on precariously by it’s delicate legs. At first, the wings are very small and wrinkled, and the abdomen is quite large. Watch closely! The butterfly ripples its abdomen, pumping fluid into the wings, causing them to expand.

Monarch butterfly adult

Adult monarch in the Tonkadale Greenhouse Monarch ZoneIt takes only a month to go from egg to adult.

The newly emerged butterflies don’t eat for the first 24 hours. They tend to rest on a plant or branch, letting their wings dry, occasionally testing out their new found flying skills. At Tonkadale, we release the monarchs from our enclosure as soon as they are ready to fly.

Monarchs hatched during the early summer months live only 2-5 weeks. Their sole purpose is to mate and lay eggs. Those hatched at the end of summer will make the long trip to Mexico in the fall and back North again in the spring. This batch will live 8-9 months. Their job is to overwinter in a warmer climate, then make their way back to start the cycle all over again.

Everyone is working hard to plant milkweed, raise monarchs, and increase their numbers. Keep up the good work!