What is an invasive species?

‘An invasive species is one that spreads and establishes over large areas, and persists. Invasiveness may be characterized and enhanced by robust vegetative growth, high reproductive rate, abundant seed production, high seed germination rate, and longevity. Some native plants exhibit invasive tendencies in certain situations.’ (http://www.nps.gov/plants/alien/pubs/whatis.pdf)

When thinking about local invasive plant species, Australian Pine Tree, Brazilian Pepper Tree and Palmetto Bush are the first to come to mind.

Australia Pine Tree

The Australian pine was brought over to Florida in the late 1800’s to provide shade, and lumber as well as provide stabilization to the ditches and canals. This particular pine is native to Malaysia, Oceania, Southern Asia, and Australia. It grows to be more than 100 feet in height, and grows 5-10 feet per year. It now covers most of the state of Florida, including much of the Southwest Florida area. Some of the ecological threats of the Australian Pine are that it produces a fruit that covers the ground entirely. This with the amount of shade it provides destroys the habitat of insects, plants and other native wildlife. It also interferes with the nesting habits of the sea turtles. There are no known biological controls for this tree at this time. Burning is recommended, however that will not prevent it from returning. When cut they do not waste any time sprouting right back up fuller than before the cut.

(This information found at: http://www.nps.gov/plants/alien/fact/caeq1.htm)

Brazilian Pepper Tree

Based on my research, I found out that Brazilian Pepper Tree was introduced in Florida in 1800s. It is a native plant for such places as Brazil, Argentina and Paraguay. It was supposed to be an ornamental plant, but after some time it has became a major pest rather than a plant decoration. It is identified as ‘multi-trunked shrub or tree with fast-growing, arching and crossing branches.’ (http://www.tbep.org/pdfs/BrazilianPepper_web.pdf). It forms dense thickens and can grow up to 40 feet in height. It spreads very fast due to its long flowering that usually lasts from late summer till November and December. It produces little red berries fruit that can be eaten by birds, raccoons and other wild animal. Since the seeds mature by December, Brazilian Pepper Tree is also commonly known as Christmasberry tree. This way the seeds are dispersed and take over more habitats, since it can grow basically everywhere, no matter the soil. Exploring Florida, one could notice them in both residential and urban landscape, as well as undistributed places. It is estimated that they occupy more than 700 000 acres in central and southern Sunshine State. To get a better notion of the problem, one could imagine Hillsborough County all covered in the plant. The main problem, and the reason for identifying Brazilian Pepper Tree as an invasive plant, is the fact that it dominates the native habitat of Florida. There are no natural predators to it. Its sap is toxic, as well as burning the wood. The most effective, yet difficult way to control its growth is to remove the roots.

(This information found at: http://www.tbep.org/pdfs/BrazilianPepper_web.pdf and http://www.floridasnature.com/exotics.htm)

Palmetto Bush

Palmetto is a large family of plants that includes both trees and bushes. All the species in the group are native to tropical and subtropical regions of America. Palmetto bushes include the scrub palmetto (Sabal etonia) and saw palmetto (Serenoa repens). Palmetto foliage is alternate and evergreen, growing in a palmate compound form.

Leaf: Alternate, palmately compound, fan shaped; leaflets very long (2 to 4 feet) and lance shaped; leaf stalk concave, extends into leaf blade 2 inches or less, and is without sharp edges; blue green in color, overall leaf nearly round and several feet long.

Flower: Small white flowers occurring on large (several feet), branched clusters, appearing in early summer.

Fruit: Fleshy drupe, nearly round, 1/3 inch across, dark blue, maturing in early fall and persistent into the winter.

Twig: Absent, since leaves appear directly out of unbranched short trunk.

Bark: Rough, gray-brown.

Form: Short bush with a round crown of large, fan shaped leaves.

If you need to kill an unwanted palmetto bush, the best way is to use herbicide.

  1. Select an herbicide containing glyphosate for killing a palmetto bush,
  2. Choose an undiluted, water-soluble formula. This will be more effective than oil-soluble esters.
  3. Spray the herbicide evenly on the bush foliage. This foliar treatment may be used on bushes up to 15 feet tall.
  4. Cover the bush from all sides with herbicide, but do not drench the leaves to the point of runoff. Avoid using glyphosate on very hot days or on plants that are severely drought stressed.
  5. Avoid spraying the plant if there is a chance of rain within six hours of application. Though you can use glyphosate at any time of the year, the most effective time is during August and September. Repeat treatment in seven to 10 days.
  6. Cut down the dead bush with an axe. Use a stump grinder to grind the stump to a depth of 1 foot below the soil line.
(This information found at: http://plants.usda.gov/plantguide/pdf/cs_sami8.pdf)
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5 responses »

  1. Amanda Koh says:

    I didn’t realize that plants could also be considered an invasive species before this article. It was especially interesting to read about how the Australian Pine Tree affects the environment because of a reason like it providing too much shade.

  2. Invasive plants? wait what are those? do they like take over our planet or something! 😛 these are some of the thoughts that came to my mind, before i began the research. I think the research enlighten some of the key issues regarding invasive plants and also would help the people who have had to deal with them in terms of figuring out ways to kill it, which in general we should’nt do BUT in this case we ought to do it for the BETTER of the environment.
    Chitra 😀

  3. I never gave any thought to invasive species; I assumed that they just co-existed with the native species, but it’s definitely interesting how plants “fight” for space, water, and light and how they affect all kinds of ecosystems, large or small.

  4. I find it hard to think of plants as potential invasive species. Growing up in Florida I learned of several invasive animal species but not any plants. It however does not surprise me to learn that several of the species I grew up considering native are in fact invasive species.

  5. James Simmons says:

    I found this article actually quite interesting. As the others are say, I never really realized or thought much about plants being invasive species. It’s definitely perked my interest to try and research into what maybe be invasive species of plants back home.

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