Hairy Bittercress, Common Foxglove, and Herb Robert can be beautiful — but you may not want to let them spread

I grew up with a mother who embodied the restlessness of the plant world – always dividing clumps of successful plantings, dealing with sudden uprisings of unplanned seedlings, and generally moving things about as season and biology allowed. If you own or live near a manicured garden, you know that it takes constant input to keep it looking a certain way. Mainly because nature abhors a vacuum and plants grow according to genes, which we only have partial control over. Humans are not masters of our surroundings, we are just a maintenance crew along for the ride of growth and decay.

The part of gardening no one likes is weeding. The end result might be satisfying but the effort involved and the endlessness of it is what drives people to the herbicide aisle. A more refined approach to weeding is trying our best to avoid it by sidestepping situations that lead to its necessity. But that’s not what I’m here to write about this week.

This topic of “weeds” is near and dear to my heart as I work to transform my yard into a more biodiverse space by including a host of native plants. Often what results from my clearing of vinca and blackberries are a host of introduced annuals laying in wait as seeds. I’m after a situation where I can leave things to a native seed bank. This may be a losing battle in a highly altered landscape but I soldier on.

However, knowing who is springing up can be a fun exercise, a way to honor the plants while learning how to usher them away. Keep your enemies close right? I find this lessens my frustration at finding a newly cleared area of my yard seeded with yet another unwanted plant. Here’s a few of the recent plants that have been on my mind and that you almost undoubtedly have seen on the Hill.

Hairy Bittercress (Cardamine hirsuta)

A diminutive Shotweed I weeded out of my garden (Image: Brendan McGarry)

Often simply referred to as “shotweed” because of their rather fun ability to shoot seeds all about when disturbed. This is obviously an effective means of seed dispersal because when left to their own devices this member of the mustard family will crowd available space. Fear not, if you desire them gone they are easy to pull up and aren’t too much of a bully in the garden bed.

The next generation of this plant has just started blooming, happy to germinate in the wet and cold, some may have started last fall. If you told me you found shotweed growing in waterlogged gravel on the North side of an apartment building, I wouldn’t be surprised. Most Cardamine species dwell in moist places and can handle shade.

There are multiple Cardamine species native to the Pacific Northwest and C. oligosperma, the Little Western Bittercress is the most likely to be confused with C. hirsuta. But don’t fret when weeding – it’s unlikely you have it growing in your garden beds. There are only a few verified records on iNaturalist across Seattle and the most recent specimen in the Burke Museum Herbarium is from 1988.

It’s easy to notice their kinship to other brassicas that we enjoy cultivating for food – I see tiny mustard and kale leaves whenever I peer close. In fact, if you are looking for plants to forage – Hairy Bittercress is edible. Their leaves have a mild peppery flavor that would be a good addition to a spring salad.

Common Foxglove (Digitalis purpurea)

An innocent looking foxglove waiting to take over my garden beds (Image: Brendan McGarry)

I have a hard time being mad at foxgloves. They are showy, beautiful plants that send flowery spires up from a pleasant rosette of soft basal leaves. A wide variety of cultivars are available, far different from the wild type plants that dot my yard and have flowers that vacillate in shades between deep purple and creamy white.

Foxgloves growing along a logging road in the Cascades (Image: Brendan McGarry)

The other reason that foxgloves are everywhere is that they are hardy, like acidic soils (which abound in our region), and readily colonize disturbed areas. This last trait is common amongst plants we consider weeds – where foxgloves are native, these are useful traits for growing quickly after a disturbance like a fire or a flood or a clearing generated by people.

Foxgloves are biennial, which means the ones I see in my garden now are on the way to their second and final year of life. If I let them, they’ll bloom in June or July. And I have to be careful because foxglove seeds are prodigious and tiny. If you’ve ever spilled poppy seeds, dumping a spire of foxglove seed is a similar sensation.

Unlike bittercress, foxgloves are not on the menu and are extremely toxic. However, the drug digoxin comes from foxgloves and is used to treat irregular heart rate and heart failure. A lot of western medicine with natural origins ends up being synthesized, but digoxin still comes from plants, though in this case a different species Digitalis lantana.

Herb Robert (Geranium robertianum)

If you can’t smell it, Herb Robert can be spotted because of it’s hairy stems (the native, Pacific Bleeding Heart, is very similar looking.) (Image: Brendan McGarry)

While there are several native species of geranium to Washington state, it’s unlikely you’d encounter one growing wild on the Hill. However, because of their prolific seed production and brittle roots, there are several species of geranium that have spread from cultivation into our feral waysides. Our subspecies of Herb Robert is from Europe, but there’s also a native population that grows across much of the Northeastern US and Southeastern Canada.

As a bird nerd, I appreciate the other name for this large genus of plants – cranesbills – but that’s about where the appreciation ends. Although they fall short of being an absolute menace like some of the plants I interact with in my yard (Yellow Archangel comes to mind), their propensity for spreading is infuriating and they are a Class B Noxious Weed in King County. Herb Rovert can completely cover large areas, even in the shade, if left to their own devices.

Learning plant biology not only brings you a bit closer to appreciating an introduced plant – it helps you deal with them. Unlike foxgloves, I pull up every Herb Robert I see immediately, any plant large enough to notice will soon go to seed and those seeds can turn around and produce more seeds before next winter. The moist soil of late winter also makes me more likely to remove the entire root, as these plants often leave behind their roots when you reach for their pungent foliage.

One reason I care about tending a garden with native plants (and not just letting things go as they might or planting from Home Depot), is because it feels like the right thing to do. But maybe it calls to you because native plants can be less work to keep alive and that’s just fine (in some circumstances that’s true but I also have many failures under my belt). For me it feels like a bit of reparations for local ecosystems that are feeling the strain of the climate catastrophe on top of everything else. The plants listed above can be treated with respect while also choosing to hold space for species that have always lived here.

But hey, here’s another reason to host more natives and less introduced plants – the native plants you procure help keep nurseries and growers in business, which are often the same places that provide plants for restoration projects. By extension, by planting natives you’re not only helping at home, but across our region. And by weeding a few undesirables, you aren’t generating a bevy of seeds to get carried off who knows where?

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