The most familiar example of an annual would be crabgrass, which germinates from seed in the spring of the year. The seed remains in the soil to germinate the following spring when growing conditions are right. This defines a summer annual. Winter annuals are very similar, except they germinate in the fall and die in the early heat of summer. Annual bluegrass would be a good example.
Fresh foliage reappears from the overwintering root system the following spring.
Dandelions would be a good example of perennial weeds. The dandelion is probably the best example of a broadleaf weed. This creates obvious problems when the weedy grasses are intermingled with desireable grasses in a home lawn. The reader will have to make his or her own determination of whether or not they choose to use chemical weed controls. Product labels are full of critical information covering all aspects of use, handling and storage of the product.