Retired professor of math and computer science having taught for 36 years at a state supported university in Virginia. United States Senators serve a term of six years in office. There is no limit on how many terms a Senator can be elected to serve.
Herbaceous perennials are garden plants that die back to the soil line when winter temperatures arrive. The plants enter a dormant period and strengthen the root system while waiting for the coming of spring.
Although lavender (Lavandula spp.) is often listed as a perennial, that is only partially correct. Lavender is actually regarded as a subshrub.