Saving the Monarch Butterfly
By Beth Lewis
The easily-recognized monarch butterfly is a pollinator and thus critical in our home gardens…but did you know the monarch is also the Texas State Insect?
What makes the monarch an unusual butterfly, aside from its stunning coloration and honor of representing Texas, is that the monarch migrates twice a year, between warm and cool climates. Other butterflies survive cold weather, but monarch adults ("butterflies") and larvae ("caterpillars") cannot.
Monarchs winter in the same places every year. The monarch population from the Eastern U.S. migrates to mountain habitats in Mexico, always to the same dozen or so locations. The Western population always over-winters on the coasts of Southern California.
If you are visiting California during the months of October through February, don't miss the spectacular sight near Monterey (Monarch Butterfly Sanctuary), where as many as 10,000 insects alight on a single tree during their migration to Southern California. You can play some pretty good golf courses nearby, too!
In the spring, the monarchs migrate to their 'summer vacation' homes.
This double migration means monarchs need food sources for both legs of their migration and for all stages of the monarch's life cycle.
What's significant to us in the area is that the flyways for the Eastern butterfly groups converge over North and Central Texas. So, our efforts are vitally important.
Southbound, nectar plants are needed because the monarchs are adults and need food for the journey. This southward migration begins in August; the insects are in their winter digs by November.
When the monarchs migrate northward, nectar sources are needed again, but food for the larvae is critical because females lay their eggs on the way to their summer habitats.
The larvae feed only on milkweed (genus Asclepias). No milkweed = no monarchs.
Unfortunately, milkweed has a bad rap. This is calamitous for the monarchs. Bad rap = no milkweed = no monarchs. More on this in a minute.
Here in the area, we want to plant the native species, Asclepias asperula ('Antelope Horn') and A. viridis ('Green'). Make a note of these scientific names so you can find these specific plants.
The best source for A. asperula and A. viridis plants is a native-plant nursery, such as Painted Flower Farm (Denton), North Haven Gardens (Dallas), Randy Johnson Organics (Terrell), or Hypermotion Design and Landscape (McKinney). Starting in spring, they often have plants but not always; you should phone first. Monarch Watch is the most reliable source for plants. It sells our North Texas native species in flats of 50 plants, which is especially convenient if you're planting a monarch garden at a school, church, or other community location.
North Texas milkweed species are Texas tough. The plants need full sun and can grow in just about any soil.
Our milkweeds are annuals, so Mother Nature can take care of next year's plants. If you want the milkweed to reseed itself, let the pods open and seeds fall where they may. Don't cover them with soil. Don't worry about winter temperatures. Come spring, the seeds will sprout. Your only problem will be distinguishing them from weed sprouts!
If you want to use seed but don't want to worry with identifying which sprouts are milkweeds, grow the sprouts yourself. To germinate properly, milkweed seeds need a period of cold. Since they're not outside with Mother Nature, you'll need to provide an assist with your refrigerator.
Place the seeds into a plastic "zipper" bag filled with damp vermiculite or sand (not potting soil). Refrigerate 4-6 weeks. Remove from the refrigerator and put the bag in a place where it will receive indirect (not direct) light. Seeds should sprout in about two weeks. Pot up the sprouts in small containers and transfer the young plants to the garden when they are three months old. Plant 24" apart. (Mature plants are about 24" high.) The time to start seeds is mid-November. This will give you transplant-sized milkweeds in approximately mid-April.
If you'd rather start with plants next year, remove the seed pods before they split open. If you forget to remove the pods, statistically you're ok because only about ½ of 1% of newly-sprouted seeds will make it to the one-year-old size without human attention – protection from rabbits and other critters; and the correct amount of water. (That's why you want to wait three months before setting out your baby plants.)
Now let's talk about milkweed's 'bad boy' reputation as an invasive plant. Milkweed is not invasive when the proper species are selected. Here's what you don't want.
'Common milkweed' (A. syriaca) is found abundantly in Canada and parts of the U.S., but not in Texas. This species is well-known to be an aggressive spreader. It does so by underground "roots" called rhizomes, which grow sideways from the main plant. Milkweed's bad reputation comes from this species! Don't plant this one!
Note: 'Tropical milkweed' (A. curassavica) is another non-native milkweed. It spreads by reseeding, is easy to grow, and flourishes year-round in mild climates. It also is easy to find and reasonably-priced in general commercial nurseries. This milkweed species has generated concerns among scientists about toxicity for the monarch over time and therefore is best avoided.
Stick with A. asperula and A. viridis.
One milkweed plant is good, but a group of three to five is better since the larvae are voracious feeders and might denude your lone milkweed quickly, leaving the larvae to starve if they can't find another plant.
Nectar plants abound in the area. A few residents plant milkweed, but more of us need to plant native milkweed to help keep monarchs off the endangered species list (and they're getting close to such a designation).
Do you have a place in your garden for some milkweed? If you do and you later see holes in the leaves, congratulations! You're raising monarchs! And, thanks!