First Monarch Caterpillars In My Garden

I’ve got caterpillars in my garden. The eggs from the first wave of female monarch butterflies started hatching a couple days ago. They took longer to hatch than usual, probably because the weather was a cooler than average in the days after they were laid. Finding monarch eggs on milkweed is fairly hard because they are small and usually on the underside of a leaf. Finding monarch larvae (caterpillars) is much easier — just look for a hole in the leaf. When a caterpillar hatches, the first two things it does are eat the egg casing then chew a small hole in the leaf. It will then expand the hole a bit before crawling off to start feeding in another location. It may do so to prevent other insects from finding it easily and eating it.

A hole on top of a milkweed leaf (left) and the same hole and caterpillar under the leaf (middle). A second example of a monarch caterpillar next to a hole in a leaf.

Monarch larvae develop through five stages, called instars, before forming a chrysalis. The caterpillars in the photo above are first instar caterpillars. The caterpillars below have molted once and are second instar larvae. Each successive instar is larger than the previous one and its coloration pattern is different. First through fourth instar caterpillars are most often found under leaves. They eat nearly constantly, except then they stop to molt.

These second instar larvae are feeding on butterfly milkweed seedlings.

So far, I have set up two butterfly enclosures on my driveway, near my milkweed plants. When I capture a caterpillar, place it on a butterfly milkweed seedling and place the seedling in the enclosure. I have collected over 30 now. Once they have eating most of these seedlings, I will transfer them to larger host plants. (I will put the seedlings back in the sun and they should recover fairly quickly.) My quest to raise and release 240 monarchs is off to a fast start, but there is still a long way to go. I should have chrysalises in a little over a week.

My 2023 Monarch Raising Project (II: Other Flowers)

[This is the second in a series, which started with a post on milkweeds.]

My 2023 Monarch Project — the goal of which is to raise and release 240 monarch butterflies — relies heavily on milkweeds. Milkweeds are the host plant for monarchs, in other words the plant monarch caterpillars eat before becoming a chrysalis. However, adult monarchs will feed on the nectar of a wide variety of native flowers. And, the more blooms that are present in a garden, the more likely monarchs are to visit it and discover the milkweeds. As with the milkweeds, I have a plan for growing a sufficient number of flowering plants to reach my goal. 

These monarch caterpillars are feeding on common milkweed.

I believe my biggest problem in past years has been too few blooms to bring the gravid female monarchs in. (“Gravid” means carrying eggs.) In the last few years, I’ve always had milkweed left after the monarchs moved on. So that has not been the limiting factor for how many monarchs I raise. This year (2022), I am working to solve this problem for next year. I have planted and maintained many more native perennials with showy flowers than I have in the past. These should return larger in 2023 and with more blooms. My goal is to have native flowers blooming continually throughout the period when the monarchs are heading north through my region. Additionally, I want to have more blooming flowers when they pass back through in the late fall. But that’s another update.

Spiderworts are one of the first flowers to bloom each spring in my area. This year, mine have already sprouted in October. If past years are any indication, they will overwinter and then start flowering in February.

I am lucky in have I have some early bloomers growing naturally in my yard. Spiderwort, baby blue eyes, and oxalis all grow wild around my house. I mow around these each year until they are done flowering and the seed heads dry out. I will also be planting a lot of larkspur, which is a very early bloomer. For “merely early” bloomers, I have multiple lance-leaf coreopsis plants that are several years old. I separated two of these older plants this fall and now have four healthy plants from them. I also planted two coreopsis plants from seed last spring. Lance-leaf coreopsis will lend their yellow blooms to the garden at a time when the spiderworts and larkspurs are starting to fade and the other plants are just budding. 

Lance-leaf coreopsis is an early bloomer. This flower attracts butterflies when little else is blooming.

After the coreopsis blooms, I have multiple gaillardia, partridge pea, and salvia plants. Partridge pea blooms heavily in the spring. Gaillardia and salvia bloom continually throughout the late spring, summer, and into fall. A little deadheading (removing faded blooms) keeps them producing flowers. Purple coneflowers, anise hyssops, and early sunflowers will also begin to bloom around this time. Additionally, four-o-clocks grow wild in my back yard. 

Gaillardia, also called blanket flower, is a prolific bloomer that keeps going all summer and into the fall.

For mid-season bloomers, when the monarchs have mostly passed, I have butterfly weed (a type of milkweed), western sunflower, California poppy, black eyed susan, and others. I have a few late season bloomers too, including aromatic aster. Most of these plants bloom at “butterfly height.” The others are still accessible to bees and other pollinators. 

Echinacea, also called purple coneflower, starts blooming mid-spring — after the early blooming flowers. It is a magnet for bees and butterflies.

With far more flowers than I have ever had, the 2023 spring garden should be more attractive to butterflies. I will also be planting new flowers in 2023, even though many native flowering plants do not bloom until their second year. I’ll also be planting and transplanting some flowers into the side yard . . . and I found a patch of my backyard that gets just enough sun for plants comfortable with partial shade. So, I can squeeze a few more plants into the yard.

Monarch butterflies in one of the enclosures I use to raise them. The enclosure is kept outdoors, so the caterpillars and chrysalises know where the sun is throughout the day. This may effect their ability to orient and migrate in the correct direction.

I will have one more post describing my 2023 Monarch Project. Then, in March of 2023, I’ll start posting weekly updates of how the project is progressing — what plants are sprouting, what flowers are blooming, how many monarchs are visiting the garden, how many caterpillars I’ve caught, and — of course — how many adult monarch butterflies I have released.

My 2023 Monarch Raising Project (I: Milkweeds)

In North America, there are essentially two main populations of monarch butterflies (Danaus plexippus). The largest population overwinters in Mexico and migrates to the northern United States — from North Dakota to Maine — and southern Canada each year. The second population overwinters in southern California and makes a shorter migration up the West Coast. Additionally, smaller populations of monarchs live in Florida or overwinter in scattered locations along the Gulf Coast.

The number of butterflies overwintering in Mexico has been trending downward since the 1970s. Milkweeds (mostly plants in the genus Asclepias) are the only host plant for monarch butterflies. Many gardeners, like myself, grow milkweed in order to provide food for monarch caterpillars. A combination of milkweeds and other native flowering plants also provides food for bees, other butterflies, and hummingbirds.

The number of monarch butterflies has been declining since the 1970s.

In 2021, I raised and released 77 monarch butterflies. My goal for 2023 is to release 240 — roughly three times as many. The reason for 240 is that for many years I raised roughly twice as many monarchs as the year before — from 7 in 2016, to 15 the next year, 30 the next, and then around 60 in 2019. To fit the pattern, I “should” have raised 120 in 2020. But there was a pandemic and other factors intervened and I only raised around 30. So, for 2023, I want to get back to the doubling — if only for a year.

To hit this target, I figure that I need four things:

1.) Sufficient milkweed to feed the monarch caterpillars

2.) Enough blooming flowers to attract the adult female monarchs

3.) To suppress any disease outbreaks in either the milkweeds or the monarchs

4.) A little luck

In this post, I will discuss the milkweeds.

In 2021, I had roughly 40 milkweed plants in my garden. These ranged from plants I had grown for many years to first-year seedlings. By the time the 77th butterfly was released, I was running low on milkweed. Using this information as a start, I figured that I would need at least one milkweed plant for every two monarchs I plan to raise. This should give me enough milkweed with a little excess. This year (2022), I have around 70 plants and I easily have enough seed for 50 more. That should be sufficient milkweed.

Milkweed is the host plant for monarch larvae (caterpillars).

In past years, I would look for monarch eggs or monarch caterpillars on my milkweeds when the monarchs were migrating through my area. I would then pick the leaf the insect was on and place it in one of my butterfly enclosures. Unfortunately, this wasted a lot of milkweed. When small, the caterpillars won’t consume an entire leaf overnight. By the next day, they want a fresh leaf. So this year, I plan to conserve leaf material by taking a pair of scissors and cutting around the egg or caterpillar. I’ll then lay that bit of leaf on a small plant in an enclosure. When the caterpillar abandons the leaf cutting, it will find itself on a milkweed plant. I can rotate partially consumed plants out of the enclosures to let them recuperate for awhile before using them again. Milkweeds are very resilient with regards to caterpillar damage. This should give me a little more leeway with regards the amount of milkweed biomass I need.

Adult monarchs will feed on the nectar of many native plants, such as these.

In a few days, I will discuss the other plants I will be growing for my monarch project. Milkweeds are the host plant for monarch caterpillars, but adult monarchs nectar on the the flowers of many plants. I have a plan to provide multiple types of flowers — blooming at multiple heights — throughout the monarch migration. In spring, I will update this website often on the progress I have made. At my location in central Texas, milkweeds start sprouting in late March and “monarch season” usually lasts from April through June.

Newly eclosed monarchs in a mesh enclosure, about to be released.