Growing Together: Open Forum

  • 1.  Questions for Monarch Experts: Tropical Milkweed in CA

    Posted 08-07-2021 03:42:00 PM
    Edited by Wesley Chen 08-07-2021 05:34:05 PM
    I know planting tropical milkweed has been controversial with numerous scientific studies against it due to possibility of messing up migration and the issue with OE parasite. Many of the large monarch conservation orgs like Xerces are completely against it but others also claim that it has medicinal effects for the infected monarchs...

    I visited a local conservation area and they plant all types of milkweeds. They have found that the monarchs prefer the tropical milkweed over the native ones. I read online that the residential monarchs or ones that breed year round, need the tropical milkweed, but I have also read online that winter-breeding is harmful for the migratory monarchs so we should just stick to natives...

    We are starting to build our school garden and have been adamant about strictly planting only natives so it is unlikely that we will plant tropical milkweed, but I would love to know if anybody has arguments for the planting of tropical milkweed, especially in our situation.

    Wesley Chen

  • 2.  RE: Questions for Monarch Experts: Tropical Milkweed in CA

    Posted 08-08-2021 11:38:00 AM
    Hi Wesley,
    Your research and consideration when planting for Monarchs and other beneficial wildlife is wonderful! I am a habitat gardener myself.
    Here in Southern CA. many of us have now switched to native milkweed and are omitting non native from our gardens. The main concern as you know, is OE. Many gardeners aren't aware that it needs to be completely cutback in late Fall to avoid issues with OE. The other issue with the tropical or non native milkweed is that sadly many growers are actually spraying the plants with pesticides before they arrive at the nurseries. Most people want to buy perfect looking plants and will generally not buy a milkweed with aphids for example, or with a few holes in the leaves. The vast majority of native plants are not treated with pesticides. The same goes for the plants we choose for pollen and nectar. Xerces has excellent information and videos on buying pesticide free plants.

    There are many considerations when choosing plants for our habitat gardens and being informed is our best defense.
    Thank you for your diligent research and for teaching the kids the value of supporting nature and our ecosystems!

    Happy gardening!
    Peggy K.

  • 3.  RE: Questions for Monarch Experts: Tropical Milkweed in CA

    Posted 08-08-2021 03:06:00 PM
    Hello Peggy, 

    Thanks for the additional info about tropical milkweeds. We decided to stick with the native milkweeds. The issue with pesticides is also something we will pay attention to when buying from nurseries. Also, is pests issues common with milkweeds? We are just beginning to plant so we haven't seen much regarding pests, but I am just curious if there are any natural ways of removing pests that you recommend instead of using pesticides.

    Wesley Chen

  • 4.  RE: Questions for Monarch Experts: Tropical Milkweed in CA

    Posted 08-09-2021 10:39:00 AM
    Tropical milkweed = aphids..always! I haven’t gotten them as much on my native plants. If it’s a light infestation you can just ignore them and leave them for the beneficials to find, if they are numerous then I usually just squish them by running a damp paper towel along the stems. You can use a stream of water as you probably know but be cautious with regard to any Monarch eggs under the leaves.
    This time of year you will likely see milkweed bugs.
    Those are not harmful and are actually considered to be a beneficial insect in the garden. If they get to be too numerous though you can prune the milkweed stems that are infested and dispose of them that way.

  • 5.  RE: Questions for Monarch Experts: Tropical Milkweed in CA

    Posted 08-09-2021 02:49:00 PM

    check out the Pollinator Posse website
    Pollinator Posse – Creating Pollinator Habitat Throughout the Urban Jungle

    Sue Bennett

    Susan Bennett

  • 6.  RE: Questions for Monarch Experts: Tropical Milkweed in CA

    Posted 08-09-2021 08:59:00 AM
    Hi Wesley,

    For places where there are overwintering monarchs (Florida has a year round population), then it makes sense to have milkweed and other flowering plants year round. For other places, most places, tropical needs to be cut to the ground if it does not get cold enough to die back in the winter. 
    I've heard tropical milkweed called the "Cheetos" of the milkweed world. They like it but it's not necessarily the best for them just like the way we like Flamin' Hot Cheetos even though the doctor says "No!" 

    Michelle Zupan
    Hickory Hill & the Tom Watson Birthplace
    502 Hickory Hill Drive
    Thomson, GA  30824
    FAX: 706-595-7177

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