Thursday, December 4, 2014

Everyone's "Favorite" Invasive Plant

Tradescantia spathacea

Moses-in-the Cradle, Oyster Plant, Tradescantia spathacea

is by any name a plant the Urban Conservation Unit and I often find growing in all types of landscaped properties, including government and school grounds. Folks are just not aware of the invasive potential of this plant and also not aware the leaves are poisonous and the sap can cause a mild to severe dermatitis reaction for many who touch it.

Unquestionably Oyster plants  are attractive with a rich green topside and purple under leaf and they grow in a neat compact form.
However Tradescantia spathacea is listed as a Category II by the Florida Exotic Pest Plant Council. While not as serious a threat to natural areas as Category I plants, Category II plants are defined as " Invasive Exotics that have increased in abundance or frequency but have not yet altered Florida plant communities". This plant has been determined to be invasive by the Invasive Species Compendium and is under review by the Florida Exotic Pest Plant Council to be included as a Category I invasive plant.

Why do we see this plant in so many landscapes? It can sprout by wind blown seed  or seeds and stem pieces carried by water from other areas. Once a plant establishes itself it will rapidly multiply and monopolize all available space. Attempts at removal result in new plants sprouting from seed when the plants are disturbed by removal.  It is easily pulled out of the ground by hand or weeding hoe, gloves should be worn and care taken to avoid having sap splash into your eyes. Once removed, bag these, do not attempt to compost as new plant will grow from broken pieces of stems and roots. You will need to monitor and remove new seedlings as they sprout.

OK.... now you know you should remove these plants, what can you replace them with? Good news! There are lots of Florida-Friendly Landscape plants you can chose from that will thrive in our Zone 10a - 10b growing area with little to zero need for irrigation once established.

Some of my favorites "purples" are noted below:

Native porter weed is described as blue porter weed, 
however, I see purple. This native has a smaller, 
more delicate flower and is pale blue-purple.This plant may sometimes grow a bit raggedy in the winter especially if it's location  in the garden has become more shady as the earth tilts more towards the southern horizon. Remove them if needed and watch them sprout out and grow thick with blue flowers once  rainy season beings in late-May. Stachytarpheta jamaicensis is also a butterfly larval host plant for our mangrove buckeye/ Junonia genoveva. This is what native "plant people" call a "twofor", beautiful plant and beautiful butterfly!

Growing awareness of sustainability and how it relates to the concept of eating fresh and eating local brings us to another great choice. An edible groundcover! You can have a beautiful groundcover and eat it too. Okinawa spinach likes a bit of shade and will sometimes wilt on the hottest summer day but it quickly recovers especially with a sip of water from your rain barrel. The photo below is saturated with color on a rainy day growing outside our shadehouse. This planting faces south. Gynura crepioides is easily grown from cuttings.

Eating purple is delicious too. A quick internet search finds several interesting and simple recipes using Okinawa spinach.
Additional beautiful and Florida-Friendly choices include Mexican Heather, Purple Heart and the spectacular bromeliad, Aechmea Malva
  Contact us for lots more information, we will be happy to
share resources, books and data base information on plants that grow well, use little water and bring beauty and life to your Florida-Friendly Landscape!

Barbara McAdam
Program Outreach, Rain Barrel & Water Conservation Workshops

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