We have some online tools for weed identification, and you can also show samples (actual plants or photos of the plants) to local Master Gardeners at a plant clinic. Perennial weeds that have the ability to regrow from root/rhizome/tuber/bulblet pieces left behind in the soil should be dug out with as much of the root mass intact as possible in order to more easily sift-out those parts for disposal, or to reduce the odds of the plant growing back. Fortunately, for many common garden/lawn weeds, species that regrow readily from pieces left behind are in the minority, like Yellow Nutsedge, Houttuynia, and Canada Thistle.

As a generalization, winter annual weeds germinate in fall, overwinter, and reach flowering (and seed production) stage in spring, before dying by summer. Summer annual weeds germinate in spring and are dead by winter. Perennials germinate at various times of the year based on the species and conditions (seed exposure to light, soil moisture, temperature), but many begin sometime in spring. Once a weed has been identified, you can learn about its root structure and/or how best to remove it. Some gardeners also allow native "weeds" to remain in the garden if they aren't too aggressive in spread, so the decision about what to prioritize removing gets further complicated by individual gardening preferences.

Miri