Which of these weeds has a thick root that extends deep into the soil?

The broadleaf plantain possesses a thick root system that extends deeply into the soil, which enables it to access moisture and nutrients that might not be available to other plants. This characteristic gives it a competitive edge over other vegetation, especially in disturbed or compacted soils. The deep-rooted nature of broadleaf plantain allows it to thrive in various conditions, making it a resilient weed.

Foxtail, crabgrass, and nimblewill, while they have their own adaptations, do not feature such a deep and robust root structure. Foxtail and crabgrass typically have shallower root systems, making them less capable of penetrating deeply into the soil. Nimblewill, on the other hand, is a creeping grass that spreads horizontally rather than developing an extensive deep root system like broadleaf plantain does. Hence, the deep-rooted characteristic of broadleaf plantain is what sets it apart in this context.