About Soni

Soni is the Greenhouse Manager and Horticulturist for the Cockrell Butterfly Center. Her job consists of maintaining the support greenhouses for the CBC, organizing plant sales, leading outreach programs, assisting with the butterfly rearing program, and spreading enthusiasm for butterfly gardening. She earned a B.S. in Horticulture from Texas A&M University and she got her first experience at the Museum as a summer intern for the CBC.

Visit the Fall Plant Sale Saturday to build or boost your butterfly garden!

Butterfly gardening is a great thing to do in the fall. Even though most butterflies will be settling down for the winter in the next few months, your garden will be ready with lots of host and nectar plants for next year’s butterflies. To get you started, the Houston Museum of Natural Science is hosting the Fall Plant Sale this Saturday from 9 a.m. to noon on Level 7 of the museum parking garage. And if you spend $30 or more, your parking is free!


Plants line the seventh floor of the Houston Museum of Natural Science parking garage, ready for the Fall Plant Sale Saturday, Sep. 26.

Most plants we offer are perfect for fall planting. Woody perennials such as salvias, duranta, lantana and many others are hardy for this area and benefit from going into the ground after the heat wave has passed and while the soil is still warm. As long as the root system has had enough time (about a month) to establish itself, the plants will be ready for winter.


Gomphrena Fireworks.

We’ve also got tips to help you maximize your planting season. For better overwintering, provide about two inches of mulch around the base of the plants and cut back the tall leggy growth to build plant strength and more roots. Also, when purchasing plants, you don’t always need to go for the plants with the most blooms. When planting something with a lot of flowers, the plant won’t put much effort into producing roots, which is what you want. Instead, they focus their energy on blooming and won’t be ready for winter. That means a lower chance of survival.



So when you pick out plants, go for bushy, healthy-looking specimens not yet in full bloom. You can even cut the blooms off when you plant, which will increase your chances of success.

Bring your enthusiasm, your green thumb and your curiosity to the Fall Plant Sale at HMNS. We’ll see you there!

Why no tropical milkweed at the Cockrell Butterfly Center plant sale this year?


Aslepias curassavica

We are sorry to disappoint monarch enthusiasts, but the Cockrell Butterfly Center has decided not to sell tropical milkweed (aka Mexican milkweed, Asclepias curassavica) any more. Instead, we will have a limited quantity of native milkweeds for sale. Recently, biologists studying monarchs have discovered that tropical milkweed may be a factor in the spread of a parasitic infection that attacks monarchs. The infection is called Oe (short for Ophryocystis elektroscirrha) and is transmitted by spores that fall from an infected female’s body onto the hostplant when she lays her eggs. The hatchling caterpillars eat the spores along with the leaves, and become infected themselves. After a generation or two or three, the infection level becomes so high that the butterfly dies (sometimes in the caterpillar stage, sometimes in the pupal stage, and sometimes as the adult).

This could happen with any milkweed – the problem with the tropical species is that it does not senesce (die back) in Houston’s mild winters but is perennial, growing throughout the year. In contrast, native species die back to the ground in the winter, and when they regrow in the spring they are spore free – so the infection cycle is broken.

Also, researchers have found that some monarchs in the southern part of the USA don’t bother to migrate if they have milkweed available. These year-round residents have been found to have very high levels of Oe infection, because they are mostly using the tropical milkweed species generation after generation. While this probably doesn’t greatly impact the migration as a whole, we don’t want to contribute to the local spread of the disease.

If you do already have tropical milkweed, one solution is to cut it back severely a couple of times a year. Even better is to remove the tropical variety and switch to native milkweed species. Unfortunately, so far these are not widely available in the nursery trade and are not as easy to grow as the tropical variety!

Aslepias viridis

Aslepias viridis

We are all learning and struggling to do our best for the butterflies. This year we will have a limited quantity of two native species at our spring plant sale: Green Milkweed (Asclepias viridis) and Antelope Horns Milkweed (Asclepias asperula).


Our next plant sale will be Saturday, March 28, 2015 from 9 a.m. to noon, or until we sell out. It will be located in its usual spot on the 7th level of the Museum parking garage. We hope you will try growing native milkweeds, and please let us know how it goes for you!

It Takes a Village ….A Milkweed Village


As the obligate host plants for monarch caterpillars, milkweeds are a staple in any butterfly habitat garden. However, milkweed is not just for monarchs! Many other insects call the genus Asclepias home, giving rise to the concept of a “milkweed village.”

Milkweed plants produce bitter tasting toxins called cardiac glycocides, and insects that eat milkweeds have evolved to use these to their advantage, sequestering the toxins in their bodies to protect themselves from predators. Most, if not all milkweed-eating insects have markings of black and orange or yellow, a type of aposomatic coloration that warns predators of their horrible flavor. If a predator such as a bird, lizard, or spider were to eat one of these insects, it would spit it out. The next such insect would be avoided, as its coloration would remind the predator of its foul flavor.

Most butterfly gardeners have encountered the bright yellow oleander aphid, Aphis nerii, which congregates on the new growth, flowers, and developing seed pods of milkweed plants. Aphids are phloem feeders, meaning that they suck the sap, along with the toxins, out of the plant’s vascular tissue.

Ladybug larva

Ladybug larva

The presence of these aphids on milkweed attracts a number of predatory insects. Ladybug larvae and adults (Hippodamia spp. and others) are important predators of milkweed aphids. Other small beetles such as mealybug destroyers, Cryptolaemus montrouzieri, and scale destroyers, Lindorus lopanthae, eat aphids along with other small sap-feeding insects. These beetles are interesting creatures in that their larval stage looks just like their namesake (i.e., mealybugs and scale, respectively).

scale destroyer larva2

Scale destroyer larvae

The maggot-like larvae of syrphid flies also eat aphids, sucking their bodies dry. Syrphid pupae look like little brown or tan teardrops. If you notice these on your milkweed plants, leave them in place to ensure another generation of these beneficial flies.

Syphid fly pupa

Syrphid fly larva

Tiny parasitic wasps such as braconids lay their eggs in aphids’ bodies. The wasp larvae feed on the inside of the aphid until they pupate, then exit as an adult wasp through a tiny hole in the aphid’s exoskeleton. The leftover brown “shell” is called an aphid mummy. These mummies are a good sign that your aphids are being parasitized. Don’t worry, these wasps don’t harm monarch caterpillars.

aphid mummy

Aphid mummies

With all of these great beneficial insects around, I hardly had to spray our milkweed crop at the museum with any insecticidal soap this year. However, if the aphid population on your milkweeds gets to be overwhelming, the best way to knock them back is to spray them off the plants with a sharp stream of water. Try to avoid damaging or knocking off any beneficial insects in the process.

Other “pests” of milkweed plants include the milkweed leaf beetle, Labidomera clivicollis. These chunky, orange and black beetles and their larvae feed on milkweed leaves.

Milkweed Beetle (Wikipedia)

Milkweed Beetle (Wikipedia)

Large milkweed bugs, Oncopeltus fasciatus, are also common in the southern United States. These oblong-shaped, sap-sucking true bugs are orange and black and mostly feed on the developing seeds, flowers and nectar of milkweed plants. They don’t usually cause much damage.

Now we come to the most familiar milkweed inhabitant – the monarch butterfly, Danaus plexippus. As we all know, monarch caterpillars eat voluminous quantities of milkweed leaves, and display the textbook aposomatic coloration of white, black and yellow stripes. Their chrysalids, or pupae, are a gorgeous jade green with gold lines and spots.


Here in Houston we sometimes encounter another milkweed visitor – the queen butterfly, Danaus gilippus. Queen caterpillars look very similar to the monarch, but they have three pairs of tentacles instead of the monarch’s two. Their chrysalids are also similar, but are a bit smaller and may sometimes be a pale pink rather than green.

Like everything else, monarchs are part of the food chain, and are preyed upon or parasitized by a number of different organisms. One of their most prevalent parasites is a tachinid fly, a gray, hairy species about the size of a house fly. An adult fly female will lay her eggs on a monarch caterpillar and when they hatch, the maggots burrow inside. The maggots live inside the caterpillar, eating its tissues, until they are ready to pupate. At that point they crawl out of the caterpillar and fall to the ground, where they pupate in the soil The maggots often leave the caterpillar after it has pupated, leaving a trail of slime that dries up and looks like white strings hanging from the chrysalis. These strings are tell-tale signs of a tachinid fly infestation.

Tachinid fly larva emerging from monarch caterpillar.

Tachinid fly larva emerging from monarch caterpillar.

Assassin bugs, Zelus sp., are frequent visitors to milkweed plants. This true bug will stab monarch caterpillars with its rostrum or beak, paralyzing the victim and liquefying its insides, making it easier to consume.

Vespid wasps are another important predator of monarchs. The familiar large red wasps, Polistes carolinus, and the smaller yellow and black European paper wasp, Polistes dominulus, both hunt caterpillars as food for their own hungry larvae. Once a wasp finds a host plant with caterpillars, she will come back regularly to check for more, especially in the summer months when wasps are the most active. This can be upsetting to butterfly gardeners. To protect your caterpillars from these all-too-efficient predators, place a screen such as a pop up or mesh laundry hamper between them and the wasps.

Polistes carolina  Photo by Val Bugh

Polistes carolina Photo by Val Bugh


Polistes dominulus

Polistes dominulus

Finally, a parasite of notable concern that specifically affects monarchs (and also queens) has emerged on the scene of butterfly gardening. This protozoan parasite, Ophryocystis elektroscirrha, commonly known as Oe, begins with a dormant spore, usually deposited by an infected female monarch as she lays her eggs on a milkweed. When the caterpillars hatch and begin to eat, they consume the Oe spores along with the leaf. Once inside a caterpillar’s gut, the spores become active and reproduce several times. When the butterfly emerges from its pupa, it is covered in dormant Oe. spores, giving rise to the next generation of infected monarchs. Mildly infected butterflies may show no sign of infection but as Oe levels build up, they eventually cause problems such as weakness, deformity, and even death.

OE Life Cycle (Monarchparasites.org)

OE Life Cycle (Monarchparasites.org)

The annual migration to Mexico each fall helps to weed out infected butterflies, which are usually too weak to make the long trip and die along the way. However, some monarchs don’t migrate and may stay in the Houston area all winter long. In the south, butterfly gardeners primarily grow tropical milkweed, Asclepias curassavica, which unlike the native milkweeds does not die back to the root in the fall. Oe spores can remain viable on the leaves of this perennial species for some time, infecting the next generation of caterpillars that eats them. As this situation repeats, it can cause populations of severely infested monarchs. We therefore encourage butterfly gardeners to cut back their tropical milkweed every spring after the first generation of monarchs arrive and eat the milkweed down, and then again in the fall before or during the migration, so that the butterflies will be encouraged to migrate and not overwinter here.

Spiny soldier bug nymph eating a monarch caterpillar. (Photo by Dan McBride)

Spiny soldier bug nymph eating a monarch caterpillar. (Photo by Dan McBride)

With all of these challenges, it’s no wonder that only five to ten percent of monarch eggs make it to adulthood. Keep in mind however, that monarchs are an important part of the food chain and without their survival and natural demise, our native ecosystem would not be as diverse as it is. In any case, human interactions with the environment have caused the most damage to monarch populations – huge amounts of monarch habitat has been lost due to the expansion of agricultural land and use of Roundup Ready crops. Planting butterfly-friendly gardens, especially if they include milkweed, can help mitigate this loss of habitat.

You can do your part by attending our fall plant sale at the Houston Museum of Natural Science. Stock up on the nectar plants that monarchs need to fuel their migration as well as host plants for native butterflies.

The sale will be held on Saturday, October 11th from 9:00 a.m. until noon (or until plants are gone), and will take place on the 7th level of the museum parking garage. Remember, the early bird gets the larva, so to speak, and don’t forget your wagon!

‘Tis the season: Fall is finally (sorta) here — and so is our Semi-Annual Plant Sale

Fall is coming! Leaves are changing color, temperatures start creeping down, and gardeners will be able to get back outside without the threat of heatstroke.

Well, in theory. This is Houston, after all.

But despite the fact that it’ll be warm until Thanksgiving, there is something we can look forward to: cooler temps! And you know what else likes cooler temps? Plants! Plants can get a little stressed out in the hot, dry summer months, and some will even go into a dormant state (which means they cease to grow to conserve as much energy as they can). This type of dormancy is usually caused by drought stress.

If you’re like me, you don’t like to spend a lot of money irrigating your landscape, so my solution is to choose plants that do not need regular watering. There are many great butterfly nectar and host plants that are drought-tolerant and we will have several of these at the Cockrell Butterfly Center’s Fall Plant Sale. We choose the hardiest perennials and annuals to help you stock up your landscape before the fall butterfly rush.

Here is my top 10 plant list for this fall:

1.Cassia splendida, Flowery Senna or Yellow Senna

Cassia splendida

1. Flowery Senna or Yellow Senna (Cassia splendida): This perennial shrub is covered in bright yellow clusters of flowers from fall through winter. It is also the host plant for several sulfur butterfly larvae. Cassia can reach heights of 6 to 12 feet tall, likes full sun, and has average water needs.

2. Fringed Twinevine (Funastrum cynanchoidies): This perennial vine is a great butterfly attractor for the fall. The pale pink flowers look similar to milkweed flowers, since they are in the same family, Apocynaceae. In fact, twinevine (unfortunately) attracts the yellow oleander aphid, just like milkweed! Monarchs will not lay eggs on the plant, but the caterpillars will eat the leaves in desperate times when milkweed is not available. Queen caterpillars will also eat this plant. This unusual plant is native to the southwestern United States, including south Texas. It is a twining vine and will need some sort of trellising.

3. Fall Mistflower or Common Floss Flower (Eupatorium odoratum, or Chromolaena odoratum): When the pale blue flowers of this plant appear, they are swarmed by many species of butterflies. The bushy plant grows 3 to 5 feet high and has low water needs. Plant in full sun for maximum blooms. Note that it only blooms for about 3 weeks, starting mid-to-late October, but the butterfly show is worth the wait.

Liatris sp., Blazing Star

Liatris sp.

4. Blazing Star (Liatris sp.): This Texas native perennial is a great nectar plant for summer and early fall. It likes full sun and is drought tolerant. The bloom spikes reach 3 to 4 feet tall. It also attracts hummingbirds!

Spicebush Swallowtail caterpillar

Spicebush Swallowtail caterpillar

5. Sassafras (Sassafras albidum): This tree is also a native to Texas. It usually occurs as an understory tree at the edge of wooded areas, so they like a little bit of shade. They can reach up to 30 feet tall and, once their root system is established, they are drought tolerant. This tree has wonderful fall color and is also deciduous, which means that they drop all of their leaves in winter. So, if your Sassafras looks like sticks, don’t worry, it will come back in the spring. Another great thing about this tree (and the reason why we sell it) is that it is a host plant for the Spicebush Swallowtail. The utter cuteness of the Spicebush Swallowtail Caterpillar, in my opinion, makes it a great ambassador for butterfly gardening. It is a favorite of many butterfly enthusiasts.

6. Corell’s Obedient Plant (Physostegia corellii):  A Texas native, this perennial likes full to partial shade and needs regular watering. Plant height reaches about 3 feet tall and the pink flower spikes bloom mid to late summer. It is a great nectar plant for butterflies and hummingbirds.

7. Brazilian Pipevine (Aristolochia fimbriata): This trailing groundcover with attractive, slightly variegated, roundish leaves, likes part shade and average watering, but will become drought tolerant when established. The plant is named after its flowers, which resemble small tobacco pipes. These unusual maroon-colored flowers attract flies to pollinate them with their “fragrance” of rotting meat. The flies think this is a good place to lay their eggs, but in reality they are just doing the plant’s bidding! This plant is also the host for the native Pipevine Swallowtail and the more tropical Polydamas Swallowtail. The funky looking caterpillars can devour the foliage all the way to the ground, but luckily the plant is ready for this and will flush out new growth from its fleshy underground storage root. If you want this plant for raising caterpillars you should plant several to have enough food for your babies.

Pipevine Swallowtail caterpillar

Pipevine Swallowtail caterpillar

8. Frog Fruit (Lippia nodiflora): This native groundcover likes full sun to partial shade and blooms spring through early winter. It is a good nectar plant for small butterflies like hairstreaks and skippers. The leaves are also a host for buckeye larvae. If you have a large open space that needs some groundcover, this is the plant for you! Otherwise, you may want to contain its vigorous growth.

9. Mexican Caesalpinnia (Caesalpinnia mexicana): This woody perennial reaches 7 to 8 feet high, and produces large clusters of yellow flowers from early summer through early winter. A great nectar plant for butterflies, it likes full sun and is drought tolerant.

Red Rocket Russelia

Red Rocket Russelia

10. Red Rocket Russelia (Russelia sarmentosa):  This tender perennial is a great nectar plant for butterflies and hummingbirds. It likes full sun to part shade and is drought tolerant, and bears “fiery” red spikes of flowers that bloom from summer to fall.. For some reason it is not found in garden centers lately, but we have it!

The Semi-Annual Plant Sale will be held Saturday, October 12 from 9:00 a.m. to noon, or until we sell out of plants. Come early, because the plants go fast!