Its cultivation as an ornamental has aided its ability to proliferate throughout the understory of mesic hardwoods. It is now naturalized in hardwood hammocks throughout the USDA Plant Hardiness Zone 9, particularly in Florida and Texas. It is classified as a Category I pest by the Florida Exotic Pest Plant Council, meaning that it is interfering with the local plant ecosystem by out-competing native plants and thereby eliminating them, as well as hybridizing with them. Christmas berry is viewed as an environmental weed in Australia, particularly in its rainforests. It has become naturalized in north-eastern New South Wales. It has also been naturalized in two islands of Hawaii. Ecological Effect The dense foliage of Christmas berry shades out native seedlings of the understory by decreasing the amount of light reaching the forest floor by as much as 70%. Its prolific berry yield furthers its ability to form monocultures, as other natives are unable to compete reproductively with the yearlong persistence of berries. These monocultures can reach numbers of over 100 plants per square meter. When the mature plants from these stands are removed, juvenile seedlings will take over the space they leave behind. The diversity of native plant species in the presence of this invasive is greatly diminished through lowered germination rates in the face of the thick cover of Christmas berry. Control Biological There has not been a biological control designated for Christmas berry. Chemical A 3% solution of glyphosate or triclopyr ester, or 4% triclopyr amine, has been shown effective in management of Christmas berry. However, the effect of glyphosate is non-specific, so the effects of the spray on the environment must be monitored. 2,4-D weakness is also exhibited, with even greater susceptibility during seedling or regrowth stages than during maturity. Triclopyr herbicide is most effective at maturity. A basal bark application of 18% v/v solution of Remedy or Garlon 4 is an effective suppressant. Cultural Thriving ground cover prior to invasion will help slow down seedling colonization. Mechanical Mechanical control of Christmas berry is a challenge. Useful methods include hand-pulling in the case of small-scale invasions. This is not a very efficient method due to the difficulty of eliminating all the surrounding berries littering the ground that will soon replace the removed material. Another option is discing, which tills the soil up in hopes of destroying the rhizomes. This must be carefully administered to prevent harm of