Question 3
Is it hard to eradicate?
Who would welcome an uninvited, surprise guest that quickly oversteps boundaries, takes over territory, devours resources and refuses to leave, even when encouraged to go? If you keep pulling an unknown, unexpected, fast-growing plant out and even dig up most of its roots, or what you can locate of its roots, suspect it as a weed. After all, does this hard-to-evict tenant, that shows your cherished nurslings no respect, belong in your garden? Many weeds have evolved specifically to survive efforts to destroy them.
All of the weeds mentioned in Q#1 and Q#2 are hard to eradicate and the reasons why are enumerated in those chapters. Similarly many of the following weeds spread fast (Q#2) and cause other plants to disappear (Q#1).
Some of these tough-to-eliminate plants benefit nature too, somehow. If you want to control erosion or to provide a self-sustaining source of food and shelter for wildlife, then these plants have a place. Judgments about many of them become subjective, ultimately.
First, Groundcovers and Their Colonies
Some gardeners believe that the word “groundcover” is code for invasive, weedy, and impossible to eradicate. And indeed this is true for several of the early spring groundcover weeds discussed under Q#1 and Q#2. But I use groundcovers extensively to control weeds. I just choose the cultivated ones that grow more slowly and that I can easily remove. Everyone’s opinion will vary. Choose groundcovers you love, with compatible microclimate preferences. Whether or not these become weeds depends on your point of view and the view of your neighbors. English ivy, Hedera helix, may escape from its erosion control function on a slope or as a weed deterrent under bushes. If it starts to climb on your house where it lifts up shingles, clogs up eaves, or degrades your paint job, or if it overwhelms other plants in the garden, it outgrows its usefulness and becomes a weed. Know the various characteristics of these groundcovers and this will help you make appropriate choices that you’ll stay happy with. Some examples: