When we’re new gardeners, we figure that anything we didn’t plant is probably a weed and pull or dig it out. We eventually catch on that sometimes our “good” plants produce useful seedlings, and gradually we learn to recognize which little plants to remove and which can stay. Ah, but then there are the mystery plants–we assume they’re probably weeds (particularly if they look really strong and healthy), but we leave them just in case they might be something desirable. And sometimes they are both: technically weeds, but also interesting enough to keep—at least for a short time.
Working with What You Get
Accepting that some weeds can double as temporary ornamentals can take some of the pressure off the drive for a weed-free garden. They might be rather attractive in leaf or flower despite their tendency to reseed with abandon, or they might fill a space where nothing else grows well anyway.
Granted, there are some plants that deserve a zero-tolerance approach. Bindweed (Convolvulus arvensis), Canada thistle (Cirsium arvense), and poison ivy (Toxicodendron radicans) are a few at the top of my own hit list. Once they come in, all three of these can spread by rhizomes. It just makes sense to pursue these creepers early and often, because every day you leave them gives them that much more chance to extend their reach.
Weeds that spread only by self-sowing offer a bit more flexibility, maintenance-wise. They’re not going to cause more trouble until they start flowering and setting seed, so you can concentrate on other tasks until then. You just need to promise yourself that you will watch them closely and remove them well before they self-sow. And if you don’t, then you have to accept the consequences of even more weeding in following years. Below are some potential seeders that I tend to tolerate, though not encourage, in my garden.
Erigeron annuum (eastern daisy fleabane): I have mixed feelings about eastern daisy fleabane. I pull out every seedling I find for months, and it still manages to elude me. It’s actually rather attractive when it flowers, with small, white, daisy-form flowers atop 3- to 5-foot-tall stems, starting here (Southeastern PA) in late spring and continuing through the summer—often into fall as well. It’s native, so I guess it’s technically a wildflower, but its propensity to self-sow all over makes it a weed in my book. It’s an attractive weed, though.
Dipsacus fullonum (common teasel): This biennial produces dense, low rosettes of deep green, prickly leaves the first year; the next year, it sends up 4- to 6-foot-tall, even-more-prickly stems topped with bold, egg-shaped flower heads that are ringed with tiny purple blooms in summer. This one is definitely a weed: it’s not native and is in fact considered invasive or noxious in some states. The darn thing is really interesting to look at, though. I dig out the first-year rosettes when I find them, or mow down the plants when they flower in the meadow. Every once in a while, though, I do let one or two plants flower, just because they are so striking. Goldfinches feast on the seeds, too.
Leucanthemum vulgare or Chrysanthemum leucanthemum (oxeye daisy): A pretty but super-prolific self-sower, oxeye daisy is another non-native that is classified as invasive and/or prohibited in some states. This is another one that I generally remove on sight and still end up with every year. If it’s in a good spot when it blooms, I’ll let it stay and flower for a bit—those bright white daisies are eye-catching in late spring–then pull it out before it makes seed. I don’t worry about it too much, though, because it doesn’t crowd out other plants even where I’ve missed some.
Daucus carota var. carota (Queen Anne’s lace): Yet another non-native that’s invasive in some areas, this biennial is well known for its lacy leaves and broad umbels of tiny white flowers in summer. I made the mistake of letting some flower early on in my front border and have pulled out seedlings for years. It grows all around here anyway, in meadows and on roadsides, so I’ll always have it around whether I want it or not.
I used to be excited to find pink-flowered plants in the meadow, because they seemed so special. Now, we can easily buy seed of pink- or purple-flowered strains.
Verbascum thapsus (common mullein): Common mullein is yet another sometimes-invasive exotic, but oh, it’s so hard to resist those dense, fuzzy, first-year rosettes, and the stout, second-year spires of yellow flowers are showy too. It isn’t generally a problem in densely planted garden areas; it’s more likely to pop up along border edges, in empty spots where spring bulbs have gone dormant, and in other areas where there’s bare soil. I enjoy common mullein as a foliage filler where space allows, and I often let it stay into the second summer.
By cutting off the main spike below the lowest flowers as those blooms are pretty much done, you can encourage new, shorter stems to branch out and extend the flowering period, if you want. Just make sure you remove the plants before the second flush of flowers set seed.
Trifolium pratense (red clover): It’s not native, but it’s often planted for forage and hay, and it pops up throughout my meadow. It’s in the garden too—possibly because it comes in directly through the meadow or maybe from seeds in Duncan’s manure (he adores red clover fresh and in his hay as well). Unless it comes up in a bad spot—in the middle of a path, for instance—I almost always leave it. Besides providing many weeks of alpaca snacks, and sweet flowers for my tea, it’s very pretty in both leaf and flower, and it doesn’t crowd out companions.
Anagallis arvensis (scarlet pimpernel): I once overhead a lively discussion about scarlet pimpernel in which someone said that if it were difficult to grow, gardeners would be clamoring to have it. I wouldn’t go that far, but this little annual does have a certain charm. Though it appears on lists of lawn and garden weeds, and some sources claim it is aggressive, I don’t find it problematic when it pops up along the edges of paths or borders. It’s low and somewhat trailing, with thin stems and small leaves, and not big or vigorous enough to weaken or smother companion plants.
Seeking out Silly Weeds
Tolerating weeds that show up uninvited is one thing; actively looking for interesting weeds and adding them to the garden is another thing altogether. Because weeds are, by their nature, prolific spreaders, it’s not all that uncommon to find natural variants if you keep your eyes open.
I’ve also seen variegated plants of garlic mustard (Alliaria petiolata), Japanese stiltgrass (Microstegium vimineum), and Canada thistle (Cirsium arvense) over the years, but I didn’t try to bring them home. (Ok—I did snitch a few seeds from the garlic mustard, which was growing along a roadside, but they didn’t germinate. Thank goodness!)
The only weird weed I’ve found here that I consider garden-worthy is a variegated, woody-stemmed aster. I’m pretty sure it is a variant of frost aster (Symphyotrichum pilosum), but I usually just call it Symphyotrichum ‘Hayefield Variegated’. It comes only about 50 percent true from seed, and the variegation tends to be unstable, but it’s interesting anyway.
Other gardeners have found much showier and more stable weed variants. Some of these are now so common that we hardly think of them as weeds anymore—unless they return to their original green forms, at least.
I am always pulling Asiatic dayflower (Commelina communis) out of my garden. The slender, branching stems weave up through other plants, so it’s easy to miss them until they start covering up their companions. While it’s easy enough to pull out most of it, the brittle stems tend to break off near the base, leaving lot of bits that can resprout. All that annyoingness, of course, perfectly explains why I have deliberately maintained a variegated form shared with me by a blog reader many years ago: Commelina communis f. aureostriata.
Winter cress (Barbarea vulgaris), also known as yellow rocket, is a common sight in farm fields around here in spring, and its bright yellow flowers are hard to miss. I sometimes find first-year rosettes in my garden and usually pull them out, but sometimes I don’t notice them until they flower the next spring; in that case, I often let them stay until the flowers start to drop off.
Wild chervil (Anthriscus sylvestris) is considered a noxious weed in several places, though not in Pennsylvania—yet, at least. I check the status each winter, because I do have a few seed-grown plants of both the dark-leaved ‘Ravenswing’ and the bright yellow ‘Golden Fleece’.
Here’s one that seems to send even normally calm gardeners into hysterics: pokeweed (Phytolacca americana). Just mention the name and they’ll start telling you how horrible it is, seeding everywhere and forming huge plants that are difficult to remove. I get it, trust me, so please don’t feel obliged to leave me nasty comments about having it in my garden. If you don’t like it, don’t grow it. I have the space for it, bees adore the flowers, and birds haunt the plants to grab most of the berries before I can collect them for the seeds.
I don’t much mind ordinary dandelion (Taraxacum officinale) seeding into the garden and grass paths, because it provides plenty of tasty greens in spring without any effort on my part. I have not had nearly as much luck when trying to actively cultivate dandelions, though. I’ve raised several “ornamental” kinds from seed but have, embarrassingly, never gotten them to live more than a year or two.
Like regular dandelion, white clover (Trifolium repens) grows freely in my paths and gardens, but it’s another one I’ve had no luck with when trying to establish ornamental selections. I think it would be great to have large patches of the silvery or maroon-leaved kinds in the grass paths. They’re gorgeous!
The bright orange blooms of tawny daylily (Hemerocallis fulva) are a sure sign that the fourth of July is nigh. It grows all over the roadsides around here and sometimes ends up in gardens too, where people want a flowering perennial that will fill a lot of space fast. It serves that purpose all right as a mass planting, but ooh, it can be a thug if you try to grow it with companions in good soil. Even knowing that, I couldn’t resist acquiring the selection ‘Kwanso Variegated’, not for its double flowers but for its white-striped foliage.
At its best, it’s a beauty, but it does need regular supervision, particularly when the new growth is emerging in spring. Each fan varies in its amount of variegation, and there can be some all-white and all-green ones as well. The white ones eventually die out, but the green ones can quickly overgrow and crowd out the striped fans. To deal with this, I cut out the all- or mostly-green sprouts in spring (cutting down into the soil with a knife to get the roots too, then removing the whole plug). Neglected patches can usually be salvaged, but that means digging out all of the plants and replanting just the variegated fans: a much bigger project.
After thinking about all of these crazy weeds for so long, I began contemplating the idea of creating an entire planting only of ornamental weeds. Then I realized that’s not too far from what I actually have in some spots. In fact, a fair number of my plants would probably be considered weedy by one person or another. In a large garden with a small budget, though, it’s almost a necessity to depend on plants that are vigorous enough to fill space by freely self-sowing or spreading without pampering. And gee, that’s pretty much the definition of a weed, isn’t it?