NOXIOUS PLANTS: BEWARE OUT THERE!

Beware the dreaded urushiol, the oil found in poison ivy (pictured), oak and sumac!

Beware the dreaded urushiol, the oil found in poison ivy (pictured), oak and sumac!

Unwelcome natives lead to itchy outing

BY Kristal Walsh, private lands biologist

Florida Fish and Wildlife Conservation Commission

This year’s warm winter temperatures have many of us itching to get outside for camping, hiking, wildlife viewing and other recreational activities. As trees and plants begin to leaf out and spring’s early blooms draw us to showy forest trails, wildlife management areas and parks, consider the following information on noxious plants so you aren’t itching to get back home! 

As a natural resources’ professional, I spend a lot of time educating the public about how invasive plant species threaten our native wildlife and habitats. So often, discussion about native plants like poison ivy (the most common), poison oak and poison sumac – which all pose a threat of a different kind – is overlooked. 

These three common Florida woody plants contain an oil called urushiol that can cause a severe rash resulting from direct contact with any part of the plants. Symptoms also can occur from indirect contact from objects like clothing, shoes or even pets which have encountered the plants. 

We are born with varying sensitivity to urushiol, and repeated exposure to the source can lead to greater sensitivity. Approximately 15 percent of people are completely resistant, but many know all too well the miserable experience that accompanies the skin irritation caused by these plants. 

The first signs may appear within eight hours of contact and a severe rash can last up to five weeks. Over the counter treatments such as calamine lotion may help temporarily, but in some cases a physician’s visit is required to treat the rash. 

AVOIDING OBNOXIOUS, NOXIOUS PLANTS

• Learn to identify the plants – Catch phrases like “Leaves of three, let them be” apply to poison ivy and poison oak and help us to identify them at the beginner’s level. But plants such as blackberry also have three leaves and can occupy the same general location as these plants, which complicates things. 

Each of these plants also loses their leaves in the winter, making them very difficult to identify. But remember: even in winter when no leaves appear, the urushiol oil is still present and can cause an allergic reaction. Your I.D. skills must be taken up a notch if you frequent the outdoors. 

Virginia creeper also commonly is mistaken for poison ivy, because it too is a vine and turns a brilliant red color in the fall, but it has a cluster of five leaves instead of three. To make matters worse, this look-alike has also been known to cause a contact dermatitis in a very small percentage of the population because of needle-like calcium oxalate crystals called raphides, which can be found on the leaves and berries. 

Poison ivy, a member of the cashew family, also is deceiving because it may appear as a shrub or a trailing or climbing vine in different locations at different stages of growth. To learn more about identification of these plants, go to https://edis.ifas.ufl.edu/ep220. 

• Location, location, location – Be familiar with the areas where these plants grow. While poison ivy can be found in almost every state, you probably won’t find this plant in dry ecosystems like sandhills or beach dunes. You will, however, find it in part sun to shade in moist to wet areas, often near the edge of a road or trail. Similarly, poison sumac thrives in moist soils and in the forest understory. Alternatively, poison oak thrives in sunny, dry locations. 

• Protection and treatment – If you will be in an area where you may encounter these plants or know you are susceptible to an allergic reaction, take precautions by wearing close-toed shoes or boots, long pants and long sleeves. Always err on the side of caution if you are unsure of the plant’s identity and avoid it. 

If you come in contact with one of these plants, wash the affected area with soap and water immediately, or at least as soon as possible. Clean all other tools, shoes and other items that may have been affected and wash all your clothes separately from other laundry. Even if you’re not sure, it’s safer to shower after a hike and take these other measures since you may have encountered these plants without knowing you did.

The Florida Fish and Wildlife Conservation Commission’s Landowner Assistance Program works cooperatively with private landowners in Florida who want to restore and conserve fish and wildlife and their habitats on their property. To learn more about managing wildlife and habitat on your property, check out our habitat how-to section at the FWC’s Landowner Assistance Program by going to MyFWC.com/LAP. You can also contact a LAP regional biologist for technical assistance.

Come visit the FWC’s wildlife management areas to experience and have fun in Florida’s great outdoors: https://myfwc.com/recreation/wild-lands/

HERE COMES COGONGRASS

As heavy equipment runs through a patch of cogongrass during the Hurricane Michael cleanup effort, the plant’s rhizomes are broken off and transported on tires and other parts of equipment.

As heavy equipment runs through a patch of cogongrass during the Hurricane Michael cleanup effort, the plant’s rhizomes are broken off and transported on tires and other parts of equipment.

Hurricane clears the way for invasive weed

BY Arlo Kane, private lands biologist

Florida Fish and Wildlife Conservation Commission

Hurricane Michael brought with it not only destruction to homes but also damage to 3 million acres of timber in Florida’s central panhandle. Much of the timber will not be salvageable and most downed timber will have to be raked into piles and burned before the forest can be re-planted. As this reclamation process begins, there is a green monster waiting to raise its ugly head. 

Cogongrass – one of the top 10 worst weeds worldwide – will be inadvertently spread by heavy equipment during the post-hurricane cleanup phase. Operations in forested landscapes is one of the most common ways this plant spreads. Cogongrass spreads by rhizomes, which are underground plant stems that send up roots and shoots from its nodes. As equipment runs through a patch of cogongrass, the rhizomes are broken off and transported on tires and other parts of equipment. The disturbed soil is a perfect medium for growing cogongrass. Each piece of rhizome that lands back in the dirt starts a new plant. 

The new plant is unlike any other you have encountered in your daily life. It forms dense mats that can spread rapidly. On clay soils, the rhizomes can reach down almost 3 feet deep. These aggressive rhizomes are thought to be the plant’s main means of survival. Cogongrass already covers over 1.25 million acres of forestland in the southeastern U.S. and is increasing every year. I have seen a five-acre patch of cogongrass explode to 40 acres in less than five years. 

WHY SHOULD YOU CARE?

As a landowner, you may be wondering why you should care? Cogongrass is an aggressive weed that can choke out even the hardiest native plant, creating a monoculture in the understory of a forest. It can grow up to 5 feet tall and burn hot enough to kill pine trees, making management with prescribed fire difficult and the potential for wildfires destroying your timber stand even greater. 

On top of everything else, this is not an easy plant to get rid of. It has been estimated that it may take over five years of treatments with herbicides to control cogongrass. The older the stand, the harder it is to control. The rhizomes have segmented nodes all along the rhizomes. These nodes can close off and prevent herbicides from reaching all of the root. Younger plants have less root system and are therefore easier to treat effectively.

Two herbicides have been shown to be the most effective at treating cogongrass: Imazapyr and glyphosate, which work best when used with a surfactant. Glyphosate is used in the early spring to prevent flowering and is combined with imazapyr in the late fall to kill the plant. Imazapyr is the most effective but it has its dangers. It is soil active and will kill hardwoods. Using it in pine stands year after year can harm the pines as well. In pines, you need to take a year break between applications. Switch to glyphosate in the intervening years.

The most effective treatment is one that starts as soon as the plant appears. As you begin your clean up, be on the lookout for small patches of cogongrass. It’s much easier to control when its young. Cogongrass has a white fluffy seed head in April and May, that is easy to identify. The leaves have an offset mid-rib but so do some other grasses. The rhizomes are the best identifier. They are segmented and have a very sharp tip.

For the next few years, be on the lookout. Cogongrass may not show up right away. If you already have some on your property, it will be spread by logging equipment, so it is unavoidable. Look for new patches and treat it as soon as you can, and you should be able to prevent its spread on your property. This will be a long-term battle, but ignoring cogongrass can be a devastating mistake for a newly planted stand of timber.

If you need financial assistance to treat your cogongrass, the Natural Resources Conservation Service has a program that can help defray some of the costs. Contact your local NRCS district conservationist and ask about the Environmental Quality Incentive Program. To learn more about managing wildlife and habitat on your property, check out our habitat how-to section at the FWC’s Landowner Assistance Program by going to MyFWC.com/LAP. You can also contact a LAP regional biologist for technical assistance. 

For more information on how to identify and treat invasive cogongrass, go to http://plants.ifas.ufl.edu/plant-directory/imperata-cylindrica/