When it comes to controlling invasive weeds, it can pay to think before you act. Do you want a quick, short-term reduction in a weed population or longer-term control? Is your weed problem limited to a specific area, or are you also concerned about adjacent fields?

A new study featured in the journal Invasive Plant Science and Management found that the best control outcomes are produced when you tailor your treatment to best fit what you want to accomplish.

Researchers conducted a two-year experiment involving invasive thistle, a weed often found in pasturelands and rangelands. Mathematical models were used to determine which of 14 mowing strategies would best support each of three different management objectives: reducing the density of an existing infestation, limiting its spread and decreasing population growth over the long-haul.

The results may surprise you. Contrary to conventional wisdom, mowing as often as possible was less effective than fewer, well-timed mowing events. That means a better outcome with less effort.

Intense mowing both before flowering and during the peak flowering period, for example, provided the best long-term control of thistle and reduced both the number of plants and how far they spread. Land managers with limited time and resources will be pleased to know that a single, intense mowing performed during thistle’s peak flowering period was the most effective approach for short-term management.

Want to know more? Read the article “Working smarter, not harder: objective-dependent management of an invasive thistle, Carduus nutans”  in Invasive Science and Plant Management. The article will be free for a month.