Which of the following is NOT a characteristic of phenoxy herbicides?

Phenoxy herbicides are a group commonly used to control broadleaf weeds. These herbicides, such as 2,4-D, exhibit specific characteristics that help define their behavior and application in agricultural practices.

Typically, phenoxy herbicides are known to have a relatively long persistence in the soil, which contrasts with the idea that they are short-lived. This longevity can lead to carryover effects in subsequent crops or unintended consequences for sensitive plants.

Moreover, while phenoxy herbicides can be toxic to certain animals, especially those that are susceptible to the active ingredients, this toxicity is often more pronounced in specific contexts rather than being a blanket statement applicable in all situations. They are primarily effective against broadleaved plants, making them desirable for crop management where grasses are the target plants.

The aspect of movement with sugar flow is relevant as it can influence how these herbicides redistribute in plants, but they don't necessarily share the attribute of being short-lived in the soil. Thus, characterizing them as short-lived does not align with their typical behavior in the environment, confirming this choice as the correct answer to the question asked.