Weeds are weeds simply because they grow so aggressively where they do not belong. They begin before the weather gets warm enough for desirable plants to grow. Some are already blooming and dispersing seed. This is why weeding is presently very important. Weeds innately compete with desirable vegetation for space, water and other resources.

Weeding should ideally eliminate target weeds before they disperse seed. Some weeds are sneaky. They bloom and disperse seed while young and seemingly innocent. Some conceal their bloom and seed with their lush foliage. They seem to know to do so during rainy weather that discourages weeding. They effectively provide their own replacement.

Some weeds regenerate vegetatively. They grow from stolons, rhizomes, bulbs, corms or other dromant storage structures. Many of these structures were dormant through winter. Some were dormant even longer. They are aware that winter is becoming spring, so now begin to grow. As they do, they generate more of the same structures, perhaps with seed.

Weeding is easiest as soon as weeds are big enough to grip. Their young roots separate easily from their soil before more thorough dispersion. Also, their soil remains thoroughly damp and soft from winter rain. However, it may be easier to eliminate a profusion of tiny seedlings by tilling. Weeding bulkier weeds, such as pampas grass, can involve digging.

Only a few weeds are woody vines, shrubs or trees. More weeds are perennial. The vast majority of weeds are annual. Regardless, the most substantial weeds are woody. Some can regenerate persistently from their stumps. Therefore, weeding of such weeds should involve removal of their entire stumps. It is important to dig rather than cut oak seedlings.

Few native species proliferate undesirably. Therefore, most weeds are exotic. Most were originally desirable, but naturalized. English daisy, periwinkle, pampas grass and broom were formerly popular flowers. Blue gum eucalyptus formerly provided wood pulp. Other weeds formerly grew as vegetables, fruits or grain. Many weeds were once forage crops.