Final answer:
Crabgrass grows more in drier southeastern US summers due to climate change, with factors including extended plant growing seasons, milder winters, and its ability to adapt and thrive in drought conditions and poor soils.
Step-by-step explanation:
As climate change leads to drier summers in the southeastern United States, the increase in crabgrass growth can be attributed to a few key factors. Firstly, warmer temperatures extend the growing season of plants, demanding more water throughout this period. However, with the advent of drier conditions, drought-resistant species like crabgrass gain an advantage and become more prevalent. Secondly, the milder winters that accompany climate change fail to effectively curb pest populations, thereby allowing for larger, more damaging infestations in subsequent seasons, which could indirectly benefit hardy plants like crabgrass that are less susceptible to pest damage.
Another aspect to consider is the adaptability of some plant species to variable conditions. As climate change alters the environment, species like crabgrass that can adapt by flowering earlier—as a response to mowing or climate pressures—will have a better chance of reproducing and thriving. Lastly, crabgrass is a plant that can flourish even when conditions are not ideal for other vegetation, which is particularly relevant in areas with nutrient-leached soils, like the famous "red dirt" regions of the southeastern US.