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What’s Blooming in Paradise: Plant Subject: Scarlet Milkweed (Asclepias curassavica )

By Staff | Oct 20, 2010

Scarlet Milkweed attracts monarch caterpillars and butterflies.

First impression: Unique looking tiny flowers what are whirly-kinda-wheel shaped. They’re segmented with top red petals and bottom orangey yellow petals. The matte green leaves are lanceolate and about 4 inches long. Milky white sap emerges from all parts of this herb when broken. Butterflies are floating all around and laying their eggs on the undersides of its leaves. You can observe this most important weed and all its attributes at the Botanical Gardens of the Sanibel Moorings.

Upon further investigation: Three reasons why Monarch butterflies populations are dwindling: milkweed, milkweed, & milkweed! Our under- used star is the host plant for three Florida butterflies — Monarch, Queen, and Soldier. A host plant is the one plant that each species of butterfly will lay their eggs on and is essential for their survival. Mother Monarchs utilize Milkweed to lay oodles of single elliptical whitish to pale green eggs right on the underside of its leaves. Like most milkweeds, it has a milky sap when pruned. This natural toxin when consumed by the caterpillar renders him toxic, which is a great survival technique against hungry predators.

Our species is from the Tropics and grows well in our zone; it can bloom continuously from spring until autumn. The flowers are small, less than an inch across, and appear in clusters at the top of two-to-four foot stalks. The sweet flowers do double duty and also serve as a nectar plant. Milkweed isn’t grown for its looks! It is leggy and twiggy growing about three to four feet tall with leaves about five inches long. The fruits are spindle shaped pods, three to four inches long, and eventually split open to release little flat seeds that drift away on silky parachutes. These airborne seeds allow our star show up all over your garden.

Once you plant this in your garden, prepare yourself for the nibbled leaves and stripped stems, a result of the neverending eating caused by Monarch and/or Queen Caterpillars. I nestle my milkweed in between other nectar plants (aka flowers), which helps hide the stubs and its unsightliness.

Once the plants are without leaves, or the caterpillars have moved on, I cut back the tropical milkweed, which usually re-sprouts from the plant’s base. New growth is fairly fast and ready for the next hungry caterpillars. Remember butterfly gardeners have to re-evaluate pesticides as their use will interrupt the life cycle of the butterfly — egg, larva, pupa and butterfly. For this reason it’s a challenge to control the other plant-damaging insects, aphids and milkweed bugs. Aphids are tiny yellow sucking insects that gather in clusters on the plant (I find they do not harm the plant and usually attract ladybugs). Milk weed bugs are orange and black and because of their toxin have little or no predators so — you guessed it — I squish-squish-squish them. Interesting note: this species is utilized by migratory Monarchs as they overwinter in Mexico.

Pros: A must for all gardens, does well in sandy soil, likes full sun, propagates everywhere, neighbors will wonder why you have all the butterflies, salt tolerance, host plant for three butterflies, pollinators love it, aphids attract ladybugs to your garden, begins the new process of not blanket spraying your garden.

Cons: Can be aggressive with seed dispersal, neighbors may be lurking in the bushes to find out your secret plant, need to squish milkweed bugs, pollinators love it, rethink/tolerate caterpillars and nibbled leaves, non-native

Conclusion: A weed is any plant in the wrong place. Milkweed is in the right plant in every garden! Who would a thought a weed could be so important in our tropical eye-catching garden. Don’t wanna miss this bloomer!

Butterfly gardeners

Don’t miss our 10th annual Southwest Florida Butterfly Conference on Saturday, Nov 6.

Call our Lee County Extension, 239-533-7504, Monday through Friday, 9 a.m. to noon and 1 to 4 p.m. or go to lee.ifas.ufl.edu/Hort/HortClasses/2010_SWF_Butterfly_Conference.pdf

See you there!