Weeds in the Garden: Are They Really So Bad?

What’s the harm in growing a few weeds? Ground cover plants, mulch, and regular tending prevent the entry of weeds into the garden to a great extent. But they still creep in. And are they really so bad? Some are flowering and pretty in their own right. So is the quest to quell weeds really worth it? Is regular weeding a necessary summer task?

Weeding by hand, the only method I find safe and effective, can be a burden. So recently, when I checked one flower bed and saw weeds blooming with tiny “daisy” faces, I wondered if I could spare myself the effort involved in pulling up those and other weeds.

In truth, the daisy-faced weeds are not much of a bother. They have a small footprint, not taking up much real estate in my garden beds. I can pull them from the ground with ease, so weeding in this case is a quick and easy task. But in my garden, a much tougher weed called Black Swallow-wort has taken up residence near perennial favorites including Stella d’Oro Lilies, Catmint, and Irises that were in bloom earlier in the season. 

The Swallow-wort is starting to girdle some of these beloved plants. And because it is a challenge to pull or dig it out, I sometimes put off weeding in areas where it grows, only to find that its stems have gained significant length in relatively little time. Eventually, its girdling coils of stem develop what appear to be beans. But these are no beans. They are seed pods which, in time, open into puffs of seeds and silky filament that is just right for carrying those seeds to new destinations. A worry.

To add to the worries associated with this weed, Swallow-wort is a member of the Milkweed family, and this makes it easily mistaken by Monarchs as a good place to lay their eggs. Unfortunately, the caterpillars that develop cannot feed on this toxic plant, so the deception is quite cruel. A plant that deceives Monarchs and turns out not to be a host at all… a plant that girdles other plants… this weed is perfect for helping me to arrive at some answers to the question I asked at the outset. It helps me to realize that fairly faithful weeding is necessary.

Answers #1 and #2 to “What’s the Harm in Growing a Few Weeds?”

Some weeds girdle and choke other plants. Some weeds can be harmful to creatures. And it is more than just Swallow-wort that has a girdling tendency, and more than just this one weed that is anything but hospitable when it comes to hosting butterfly larvae. And so, that brings me two answers to the question, “What’s the harm in growing a few weeds?”

Answer #3

Weeds take up space in the garden and often grow at a rapid rate. They can crowd out perennials and annuals that have been purposely selected and planted with care. Some can grow large enough to reduce other plants’ access to sunlight, acting like massive buildings along a city block, relentlessly shading what is beneath them from the light. This can be a problem. With the ability of some weeds to block other plants from sunlight, weeds can begin take over the garden if weeding is not undertaken.

Answer #4

When weeds are left in a garden, they take in some of the water and nutrients that other plants require. Some gardeners counter this statement by noting that certain weeds have elongated roots that draw from deep down in the soil, bringing nutrients up closer to the surface and making those nutrients more accessible to nearby plants with shallower root systems. More beneficial than harmful? More harmful than beneficial? For me, the fact that weeds undeniably take in some of the hydration and nourishment in the garden bed is a definite worry, as “some” is too much when garden resources are scarce… and face it, they are often scarce.

Now, certain plants might spark worry because of their names—take Milkweed and Butterfly Weed as examples—but these are well worth the water and nutrients they utilize. We nature lovers know better than to pull these beneficial beauties (now helpfully put in a Native Plants category by most gardeners). Keeping these plants in the garden for Monarchs and other pollinators is important. But unless we really want Dandelion tea or don’t mind coming across the painfully prickly Canada Thistle which, like Swallow-wort, tries to invade my garden each year, we really should get weeding. 

Now, Thistles provide a good example. They would be everywhere in my yard if I didn’t do some regular weeding, making sure I get out as much of their taproots as possible. While pollinators may like the Thistles once they are in bloom, I have to ask, “Can I handle their size at maturity?” (Their prickly broad stems and foliage take up lots of space once these plants have had some time to grow.) “Can I control their seeds after I enjoy their purple blooms—seeds that seem to take hold wherever they fall?” No. (I know this from experience... experience that stems from times when I was lax in my weeding.)

Summing Up (and Committing to Pulling Up… Weeds)

Having shared all this, I personally land in a place where I think regular weeding is important. I am "all for" clover lawns and mow-free months; I do see the beauty in some plants that blow in on the wind (or more specifically, emerge from seeds that do). But when it comes to weeds that are the likes of the Swallow-wort and Canada Thistle I mentioned, early and regular weeding is the only way I can keep my garden in good shape. 

Out of necessity (lack of time and energy), I will overlook some weeds, and with any luck, those that I overlook will not do too much damage to my perennials and annuals. But in general, now that I have given weeds so much consideration, I think I am going to continue reminding myself to keep weeding, mulching, and purposely adding ground cover plants that will make it hard for weed seeds to reach the soil and germinate. Endless work? Sure. But it is work that is worth the effort.