The Lion and the Lamb: Roses and Monarch Caterpillars

by Rita Perwich, Consulting Rosarian, San Diego Rose Society

“The caterpillar does all the work, but the butterfly gets all the publicity.” ~George Carlin

The phrase ‘the lion and the lamb’ is an expression that expresses peace between two unlikely partners. This title might seem incongruous when applied to roses and caterpillars but in actual fact it describes to perfection the partnership that plays out in my garden between my roses and monarch caterpillars and butterflies.

Monarch caterpillars have many endearing qualities. They are really attractive caterpillars with yellow, black and white stripes. They create a beautiful green chrysalis flecked with gold dots and a gold stripe within which they pupate and metamorphose into a lovely, graceful orange, black and white monarch butterfly. But for me, one of their most lovable qualities is their monotrophic diet: all they eat is milkweed.

We all love seeing butterflies wafting through our gardens and we all know that before those butterflies became butterflies, they were very hungry caterpillars that ate and ate many plants including our roses. Eric Carle describes the caterpillar’s eating frenzy perfectly in his classic book, The Very Hungry Caterpillar. So the gardener in me enjoys only the butterfly stage of the members of the order Lepidoptera…except when it comes to monarch caterpillars. These caterpillars are so welcome in my garden!

In fact, I took out the sidewalk lawn and replaced it with four large rectangular planter beds in which I grow colorful nectar and pollen plants and flowers to invite and tantalize pollinators, and I grow milkweed specifically to let the monarch butterflies know that their family is very welcome in my garden. This bias in favor of monarch caterpillars may seem unfair to all the other caterpillars that I snip in half. But

I can trust monarch caterpillars in my rose garden. Unlike other caterpillars, I know they won’t chew up my roses’ leaves or feed on my rose buds and blooms. In short, monarch caterpillars exist together very peaceably with my roses. In appreciation, I treat these caterpillars with loving kindness and ensure that there is always a plentiful supply of milkweed for them to chomp on in my garden. In return, they bestow me with the joy of watching them grow and transform into butterflies that glide and flit gracefully in gardens in the neighborhood pollinating plants and bringing delight.

So, for the third year in a row a successful monarch wonder plays out daily in my sidewalk garden. I witness the newly hatched tiniest caterpillars munching their way to becoming big hungry caterpillars. The biggest caterpillars then make their adventurous trek across the sidewalk to the roses planted outside our wrought iron fence.

The first time I spotted a monarch caterpillar on a rose leaf I chided it and carried it over back to the milkweed with a gentle reprimand. But then I started to notice the chrysalises hanging off and adorning rose stems, rose leaves and our wrought iron fence. The caterpillars aren’t making the voyage across the sidewalk to eat the roses. They are making the bold crossing because they somehow innately know that there are safe and secret places to make chrysalises among the roses.

Another super COOL event is that through these caterpillars I am making new acquaintances daily with the cutest children! Some spot the caterpillars. Others discover them because when I hear a child say, “Mom, look! Butterflies!” I can’t resist going out to introduce them to all the caterpillars from the tiniest to the largest. I point out the green and gold-flecked chrysalises, the chrysalises that are translucent black with the orange wings showing through, and the empty chrysalis casings that may look flimsy but can hang on for months. I explain to them that the chrysalis is actually always clear and it is not the chrysalis that changes color. The color change is that of the pupa inside that starts green and then gradually transforms itself into the adult colors.

So there are a lot of children learning excitedly about the wonder of nature and the wonder of the monarch butterflies right outside my rose garden. They pose questions with such wide-eyed amazement, and I know they are storing away their happy first impressions of these pretty striped caterpillars, chrysalises and butterflies among the roses. Some of these families are now growing their own milkweed with ‘starter’ caterpillars from my garden. Milkweed does seed itself and because I trust the monarch caterpillars so implicitly I have even started to allow milkweed to seed itself amongst my roses. This saves the caterpillars the treacherous march across the sidewalk where they risk being trodden upon.

Facts about Monarchs. The monarch butterfly undergoes four stages of metamorphosis: egg, larva, pupa and adult. Eggs are usually laid singly on the underside of a milkweed leaf plant. They eclose (hatch) as caterpillars in 3 or 4 days and immediately start eating milkweed. In this larval stage the caterpillar goes through five major, distinct stages of growth (called instars). Each instar molts and gets progressively larger. Depending on various factors such as temperature and food availability, each instar usually lasts about 4 to 5 days.

As it eats, the caterpillar stores energy in the form of fat and nutrients to carry it through the non-feeding pupal stage. The fifth instar or last stage of the larva is often found away from milkweed plants as it is now seeking a suitable place in which to pupate, the interim stage when the caterpillar magically transforms itself into a butterfly.

Attaching itself to a plant or other suitable support using silk it produces, the caterpillar hangs head-down in a “J” shape. It sheds for the last time as it encapsulates itself into a chrysalis. Monarch metamorphosis from egg to adult can occur in as little as 25 days during the warm summer temperatures but takes longer during cool spring conditions. In the summer, the pupa matures in about 10 to 14 days during which time the adult butterfly is forming inside. Within a day or so before the butterfly emerges, the exoskeleton is complete and the wings have become their final vibrant orange, black and white colors. The chrysalis that appeared green is now bluish-black. As the adult butterfly emerges it hangs upside down for a while until its wings are dry. It flaps its wings to pump fluids into them. And then it is ready to set off on its wondrous first flight! Twenty-four hours later, the butterfly purposefully starts its search of nectar plants.

During the breeding season adults reach sexual maturity in four or five days, and monarchs typically live for two to five weeks during their breeding season. However, migrating monarchs can live up to 8 to 9 months, and their last generation of the year does not reach maturity until over-wintering is complete.

Friend of the Monarchs. When we care deeply about something, we realize that there is no end to the questions we can ask and the answers we need to seek. Thank goodness I attended a master gardener advanced education class on monarch butterflies. It was presented by Judith Wolinsky, a fellow San Diego Master Gardener. Wolinsky is a monarch butterfly and monarch garden expert, and the founder of Monarch & Friends. This is a group of mostly local monarch gardeners and those interested in monarchs, and it’s free to join. The email address to join is monarchandfriends@gmail.com.

I am so grateful to Wolinsky for her generosity in answering all my burning questions about everything to do with the monarchs, and for assisting me in getting the correct scientific facts for this article.

Facts about milkweed.

The toxic cardenolides in milkweed provide protection to the monarch caterpillars from many predators including birds. There are two kinds of milkweed, native and non-native. There are six native San Diego varieties and various non-native ones. I am growing the tropical milkweed which is easier to find in the nursery. Unlike tropical milkweed, native milkweed goes dormant over the winter. This means that we can have monarch gardens all year around in San Diego. That may sound like a good thing but it is not. Research has shown that a monarch parasitic protozoan called Ophryocystis Elektroscirrha (OE) increases in percentage when milkweed does not go dormant. This is a big problem because OE infected butterflies may not be able to fly well, have a healthy weight or live as long as non-infected monarchs. Until recently monarch experts heavily promoted growing only native milkweed. However, in recent years a compromise has been found. We can duplicate native milkweed dormancy to prevent female monarchs laying eggs by cutting back tropical milkweed a few inches above the ground by mid-November. We then re-cut the milkweed if needed to maintain it at that height through mid to end of February. At each cutting, the leaves and stalks must be carefully cut and immediately disposed by bagging to avoid dispersal of any microscopic OE spores. When cutting milkweed be very cautious. I wear sunglasses and disposable gloves when I cut milkweed as the sap can be very irritating to the skin and can also be very dangerous if it gets in your eyes.

Female monarchs lay hundreds of eggs over the season. To prevent the female from laying eggs some time before cutting the milkweed back, Wolinsky suggested that I cover the milkweed with an inexpensive paint strainer bag (1 or 5 gallon, found at home improvement stores or on-line), leaving the bottom open for the caterpillars to move across the sidewalk to make their chrysalises. I will definitely implement this suggestion as last year I was forced to delay cutting back my milkweed as I kept seeing caterpillars.

On the plus side of the tropical non-native versus native milkweed debate, Wolinsky states that in various research studies that she has read, the former has been found to have higher levels of the protective cardenoloides. She says that some monarch gardeners who grow both non-native and native milkweed in their gardens have told her that the female butterflies appear to like the tropical milkweed better than the native milkweed to lay their eggs, but others have told her the reverse. In my garden, there is scarcely a nibble on the one and only native milkweed plant that I planted in the late spring.

There is a Fly in the Ointment. Up to now, my relationship to insects has been simple. In my mind, insects are perfectly and simply sorted: an insect is a pest if it causes damage to my plants and a beneficial when it is a predator of a pest insect. But with my concern for monarchs, I have discovered that my simple method of sorting of pests is actually like most matters in our lives: not at all simple and actually quite complicated.

I have long lauded and sung the praises of the tachinid fly which is considered a beneficial in the rose garden. But my feelings about this fly have changed dramatically. The tachinid fly poses a major threat to the survival of the monarch caterpillars and chrysalises. The tachinid fly larvae can infest and kill caterpillars. The adult lays eggs on the back of a caterpillar and once hatched, the larvae burrow into the caterpillar and start feeding on it. When the monarch caterpillar gets ready to pupate and hangs head-down in its “J” shape, the tachinid larvae kill it. Each tachinid larva then makes a “silk” string, descends and burrows in the soil where it forms a hard shelled pupa and emerges later as an adult. The tachinid larvae sometimes wait until the caterpillar has become a chrysalis to kill the pupa. Lately, I have also observed spiders, also a garden beneficial, ‘silking’ milkweed leaves together. I suspect that they are doing this to hide in the milkweed to prey on the monarch caterpillars. To keep the monarchs safe from tachinid flies, spiders and other predatory insects, some monarch gardeners raise their monarchs eggs and/or caterpillars in mesh butterfly cages. 

Leaving it Up to Nature. As gardeners, we want to be awash in peace, in touch with nature and interconnected with all earth’s creatures. But in a garden, peace-rattling factors come at us from all directions. Our roses get chewed and marred by fungal diseases. And, monarch caterpillars get attacked by tachinid flies and spiders, and infected with OE spores. My decision to not use pesticides in my garden requires the willingness to give up some control and to trust that somehow nature knows better than I. At times, it takes courage and a massive leap of faith because I know that letting go can lead to unpredictable and unwanted outcomes. But I firmly believe that trusting nature leads to balance and a healthy garden and a healthy ecosystem, and I get satisfaction in working with nature and allowing nature to reciprocate and help me. So I am going to leave my industrious monarch caterpillars in my garden and trust that the majority of them are going to transform and become beautiful butterflies. It is awesome to provide children with their first glimpses of how wondrous nature is and I can’t help but believe they will always remember the pretty striped caterpillars among the roses. It makes the world seem so simple, kind, gentle and good. Truth be told they may not remember the roses but the roses are the setting for this wonderful transformation of life.

‘Stop and smell the roses' is a wise saying that uses roses as the vehicle to convey an important wellness message. Roses and monarch butterflies provide the prompt: our inclination on seeing a monarch butterfly is to stop and pause what we are doing, and our inclination on seeing a rose is to bend down to smell it. Roses and monarch butterflies coexist peacefully and together are partners in creating harmony. The rose garden embellished with monarch butterflies fluttering in the breeze adds yet another dimension to interact with nature, dwell deeply in the present moment, feel truly alive, and smile.

All photos by Rita Perwich