Every spring, one of my go to filler plants for patio pots is the pink/orange variety of lantana. It is one of the last plants to succumb to cold temps in the fall and provides 6 months of color. In other parts of the world the plant is not looked upon so favorably. Since 2023, lantana has been deemed a serious weed in India and one of the 100 most invasive plants in the world, with a high invasive potential due to its rapid growth and adaptation to varied environments. As it is found in both cultivated and uncultivated land, it poses a threat to both native biodiversity and crop productivity. During a visit to the Western Ghats of India last year, I saw large piles of the plants that had been pulled from the ground and were ready to be burned. In the US, it is considered invasive in Florida and Hawaii.

Even in cold climates, introduced plants can become invasive and troublesome. Lupines were brought to Iceland from Alaska to combat erosion and improve soil health by fixing nitrogen from the atmosphere into their roots. Unfortunately, they have spread aggressively and crowd out the delicate native Icelandic mosses and ferns. An important difference between Alaska and Iceland that has contributed to the spread is the lack of trees in Iceland. Lupine grow in open prairies with plenty of sunshine. The forests of Alaska limit the spread of lupine to open areas around streams.

Trees can also be invasive. While commercial forests provide lumber for New Zealand, they also easily spread their seeds outside of the managed forests to surrounding hillsides, crowding out native plants and animals. Due to the tropical climate of the island, the trees can grow three times as fast as in colder climates. It is estimated that up to 25% of the island nation is at risk of being covered by invasive wilding pines in the next 30 years if aggressive measures are not adopted to control the spread.

Minnesotans are well aware of invasive buckthorn plants that have become exceedingly difficult to control. They were brought here from Europe as a popular hedging material and quickly became a nuisance plant, crowding out native plants and animals in the mid-layer of the forest. More recently, burning bush sales have been restricted since 2023 due to similar invasive behavior as buckthorn.

What can we as Minnesotans do to combat the threat of invasive plants? Awareness is important as well as action. There are multiple volunteer groups working to eradicate buckthorn from public parks and welcome new volunteers. If buckthorn is found on your property, remove as early as possible with one of several methods. If you have a burning bush on your property, replacing your Burning Bush for native shrubs like Aronia (Black Chokeberry) or Serviceberry, which offer similar fall colors and support local pollinators. can prevent further environmental damage. Early control can prevent the more widespread damage that has occurred in New Zealand and Iceland.

Have a question about your lawn or garden? Our Ask A Master Gardener web page has resources. Also look for our volunteer booths at your local farmer’s market in the summer for a helpful interaction.

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Photo by ju demu on Unsplash

Photo by Jeffrey Hamilton on Unsplash