An alien plant is usually distributed by man. The natives are undisturbed by man and are not foreign to our region. I also learned that the backyard would contain annual, biennial, and perennial plants. The first group is annual plants. Their life span is completed in one year.
Most annual plants are herbs.
The herbs remain in a small size and their stems are usually green and strong. Biennial plants have a life span that is completed within two years. Biennial plants do not reproduce flowers and seeds until their second growing season. Perennial plants live for more than two years. Perennials include trees and shrubs and many herbs.