Often when we talk about “weeds” at Tree of Life, we try to use the term “misplaced plants” instead, sometimes getting a look or two. We do this for a couple of reasons. First, we want to remember that these misplaced plants are part of an ecosystem somewhere, even if it is Europe or Asia. We also want to remember that sometimes weeds can be native, and just because we didn’t put them there, doesn’t mean that they can’t be there. By using more precise language we can say that this is a plant we don’t want in our garden without putting it into a category of “bad plants”.

Especially with seeded meadows and other ruderal (plants that spread mainly by seed) gardens, it’s important to maintain balance to keep one species from taking over. Sometimes the same plant can be a weed in one garden but not in another and since it is hard to tell which plants should stay and which should go, we came up with five criteria to help guide our garden stewardship.

This Sweet Pea grows over a fence at a commercial property in Mead, CO — A wild Sweet Pea grows over a commercial fence in Mead, CO

Do I like it?

Some plants have been put into the weed category, and we pull them out without stopping to ask ourselves if we like it. Beth Chatto famously used biennial thistles in her gravel garden, showcasing their cactus-like beauty. If a plant is a “weed” but we like the bloom, texture, color or some other element, it is often ok to let that plant thrive. Some plants like Mullen, Scotch Thistle and even Bind Weed have features that we may consider desirable in our gardens. Bind Weed was once considered a wild Morning Glory that could act as a ground cover, though I do think it’s ok to pull this one every time. Other plants like Sweet Peas or Milkweed are some plants that may self-sew in our gardens and provide some unexpected beauty.

Erigeron canadensis or Horseweed is welcomed into this naturalist planting

Is this plant displacing plants that I would rather have in my garden?

If this plant is going to make it harder for some of our preferred species to thrive, it is probably best to remove it. Things like bind weed, kochia, or mallow weed are fast-growing and can easily out compete our perennials. Sunflowers can even out-compete smaller plants with its large leaves and fast-growing habit. Though they may be small at the moment, they can quickly become a garden bully with their fast and competitive growth patterns.

Dandelions are quick to take advantage of unused, disturbed soil

Will this plant cause a larger problem in a year or two?

Sometimes inviting one plant into our space can result in a whole colony in a year or two. Species like Mullen or Biennial Primrose will produce thousands of seeds at maturity that could result in a hostile takeover of the garden. For this reason, it is important to understand these plant’s lifecycle, so we can prevent them from becoming a problem in the garden. Volunteer tree sprouts likewise can be quick to sprout and can quickly become a larger problem if you don’t want a tree there. Other plants like Smooth Brome or Bindweed can spread by seeds, rhizomes or stolons and can slowly encroach on our gardens.

Kochia will create a dense monocultural carpet if allowed to reproduce

Is this plant good for pollinators?

Some unwelcome plants bloom in the early spring before many of our perennials, providing a valuable food source for pollinators. Even though Dandelions may self-sow into our yards, inviting diversity into our turf lawns isn’t always a bad thing. Plants like Dandelions and Blue Mustard will bloom as early as April, taking advantage of the spring moisture. Leaving these plants in our spaces can help support honeybees and native pollinators in the early spring.

Dandilions and Blue Mustard create dense blocks of color and support pollinators in the early spring

Is this plant protecting the soil and locking in moisture?

In some instances, species like spotted spurge or purslane will quickly cover bare spots in the soil. Sometimes these low-spreading species (especially Bind Weed) keep other plants from reaching full size, but by covering the soil they retain moisture and prevent soil degradation and compaction.