What are Invasive Plants?

Throughout Madera County, destructive, non-native plants have permanently taken over hundreds of thousands of acres of formerly productive agricultural and wildlands to the detriment of ecosystems and economies depending on this land. Although many non-native or invasive plants exist in Madera County without causing harm, some are so invasive that they can spread across landscapes, replacing desirable plants with acres of nothing but noxious weeds. Surprisingly, many invasive plants were planted intentionally.

How did Invasive Plants get here? 

Invasive plants are often, either accidentally or on purpose, imported by individuals, their animals, their vehicles, or by hay/straw or gravel deliveries. Without the natural competitors, predators, and/or pathogens that provide a normal control in their country of origin, they cannot be kept in check. Sometimes plant nurseries sell invasive plants as “hardy” species.

What are some examples of local invasive plants? 

• Arundo donax, frequently referred to as “bamboo,” is often seen on our waterways. Arundo was originally planted intentionally for bank stabilization efforts, but has taken off. It requires maintenance and meticulousness to remove as it loves to come back. Again and again.
• Spotted knapweed puts out a poison that kills neighboring plants, allowing it to dominate the landscape at the expense of native plants. It is bad forage for livestock and wildlife.  Once established, it does not hold the soil in place well and soil erosion and increased runoff result.
• Yellow Starthistle is poisonous to horses, causing “chewing disease.” It spreads rapidly.
• Italian thistle crowds out native plants, reduce forage for livestock and wildlife; and because it is prickly and painful, degrades recreational areas.
• Brooms exclude native plants and increase fire danger because they are extremely flammable.

Resources

Field Guide to Invasive Non-Native Weeds of Mariposa, Madera, and Fresno Counties

Top 10 Noxious Weeds & Invasive Non-native Plants of Mariposa, Madera, and Fresno Counties