April 26, 2015 -- Five Monarch Caterpillars feeding on one Tropical Milkweed plant at the Garland Community Garden. These five caterpillars stripped the plant down to the stem in less than three hours. Because it was still early in the season, this plant had not even produced flowers yet. Unfortunately for the caterpillars there was no more milkweed and no more protective habitat cover. They were apparently picked off by predators as when I returned with a few potted milkweeds a few hours later, they were all gone.
When it comes to establishing milkweed, the hardy tropical milkweed (Asclepias curassavica) I’ve found is very easy to establish and is widely sold in most nurseries whereas the varieties of native milkweed are difficult to find. This is likely due to the fibrous root system of tropical milkweed which readily lends itself to pot life where as the long taproot of the native milkweed does not and thus is not such a viable commercial entity for nurseries. [For those who may not know: Plants are characterized by one of three types of root systems: taproot, fibrous, or adventitious (roots that form on plant parts such as stems or rhizomes as ivy, iris and Horsetail (Equisetum arvense). ] The taproot of the native milkweed grows fast and long.
However, one of the problems with tropical milkweed is that it does not die back in the winter south of the DFW area where there are no killing freezes. Thus some argue this encourages Monarchs to overwinter and not migrate to Mexico. Also in warmer areas such as south Texas and Florida, the leaves are prone to mildew which some studies indicate creates diseases among the Monarchs who come in contact with these plants—diseases they can pass on to subsequent generations.
Plus, let's face it, the tropical milkweed is not native to Texas and thus we have no idea what impact it may have on our ecosystem here in North Texas but we can be fairly certain that the impact will not be great--and because of its prolific seeding capability, the tropical milkweed holds a good potential for developing into an invasive species.
I PLAN TO CONTINUE TO HAVE TROPICAL MILKWEED IN MY GARDEN THIS YEAR
So all that taken into consideration: I plan to continue to have tropical milkweed in my garden at home as well as the Garland Community Garden--at least for the rest of 2016. First of all, I want to see how well the native milkweed we are planting does in terms of growing and providing habitat for Monarchs.
I know first-hand that tropical milkweed has supported at least 16 Monarchs here in Garland in the fall of 2016. Without tropical milkweed, the world would be without at least 16 Monarch butterflies and many more as I have several friends I know who have captured and released monarchs here in Garland that fed on tropical milkweed.
PRECAUTIONS I'LL TAKE.
First of all, I'll monitor all tropical milkweed plants under my stewardship with extreme care. I will not allow any seed pods to mature. I'll pick them all off while they are still green. In the fall of 2016, if the planting of our native milkweed species are successful, I will dig up all tropical milkweed in my garden and the Garland Community Garden in the fall. I will keep five plants back in pots that I will bring in my home for the winter. These will be there in the event we find any late bloomer Monarch caterpillars in November or December as we did this year. Without those tropical milkweeds, our story of Happy 2016 the Monarch would not have had a happy ending. In the spring of 2017 I want to see how quickly the native milkweeds mature. Ideally they should be mature enough by the end of April to support Monarch caterpillars. If they are not, I'll continue to offer tropical milkweed with the aforementioned precautions. The goal here is to support the re-establishment of our Monarch population.