Erasing the Green Blur: Foxglove, A Naturalized Invader

In ecosystem restoration, the goal is to try and return a degraded natural area back into what it once was. Put simply, restorationists try to turn back the clock and recreate the habitat or plant communities that existed before humans began to alter the land.

According to the Center for Biological Diversity, by eliminating factors that contribute to landscape degradation( e.g. suppressing wildfires, diverting streams, etc.), restorationists are able to start recreating the natural systems (i.e. food webs) or environmental conditions(i.e. seasonal flooding) that helped to support a particular habitat type or vegetation community.  

Restoration ecologists will spend a  good proportion of their projects trying to eliminate and control the invasive plants that reside within a project site. An invasive species is defined by the United States Department of Agriculture( USDA)  and the U.S Forest Service as a plant or animal that is not native to the environment it currently inhabits. The majority of all invasive species are detrimental to the environment they establish themselves within.

Often causing ecological damage to the native vegetation communities, altering the natural systems that sustain the landscape or threatening economic interests for humans. Removing invasive species from the landscape is a process that can take years of repeated manual and chemical processes.  In time sites will require less and less treatments as the native vegetation becomes established enough to crowd-out invasive species.

Handling the presence of non-native plants is not always a clear-cut situation.

For every true invasive plant, there may be at least one or two non-native or naturalized plants that have worked their way into the vegetation communities. The USDA classifies a non-native plant as a plant that was deliberately introduced into an environment where it did not historically exist.

These plants, often ornamental garden plants, are not always capable of becoming an invasive species. Nor do they always cause ecological harm to the environment even if they do escape. A naturalized plant, on the other hand, is a plant that has existed within the environment long enough to establish and sustain itself within the environment without human assistance.

More often than not, naturalized plants integrate themselves into plant communities and become impossible to eliminate completely. One of the most common and most recognizable is digitalis purpurea, the common foxglove.

Open up any gardening book, and you will likely recognize this flower, one of the most distinctive flowers utilized within gardens and urban landscapes. Endemic to Western Europe, this flower made its way into the North American landscape centuries ago and has since established itself within the environment.

This biennial plant is able to thrive within an environmentally variable landscape. Biennial plants depend upon a two-year life-cycle; the first year of which is when they emerge as a round cluster of vegetative leaves (called a basal rosette) but produce no flower. Only in their second year do biennial flowers produce flowers. Foxglove can be recognized in their basal rosette form by their oblong, often spoon-shaped leaves.

This evergreen foliage is soft to the touch and has been described to be gently serrated or toothed on the edges of their leaves according to the North Carolina Extension Gardener Program at North Carolina State. In their second year, they produce the beautiful, showy, and pendulant bell-shaped flowers for which they are recognized.

According to the Missouri Botanical Garden, the name foxglove comes from the flower’s resemblance to the fingertips of gloves. Remarkably, the petals on foxglove are fused into a singular structure called a corolla, which is often purple in color. Decorated with leopard-patterned speckling, these flowers are heavily utilized by bees.

Not only the bees utilize these flowers, however, but foxglove also has a long-standing relationship with homeopathic and modern medicine. A component found within this toxic plant may help control heart conditions. WebMD states that foxglove is heavily utilized to make heart medications such as digoxin. Though it may aid in mitigating congestive heart failure and irregular heartbeats, it is strongly cautioned against using this plant without medical supervision.

I frequently come across this flower whenever I am working within forested landscapes here in the Pacific Northwest. Foxgloves ability to grow in moist, acidic soils (particularly soils that have a good amount of organic material) may explain its prolific presence within the coniferous forests of the Pacific Northwest.

However, the University of Wisconsin-Madison reports that foxglove can also be found along roads and in disturbed areas; especially mountainsides. Since it was first introduced into North America, this plant has established itself within the western and northeastern United States, but the USDA also mentions that common foxglove can be found in Alaska and Canada as well.  

The Missouri Botanical Garden cautions that in the right conditions, this flower has been known to create large dense colonies within the environment. Yet it is only considered an invasive species within a handful of states.

This is likely because when one weighs the ecological and economic costs of treating foxgloves within a habitat restoration site, against more aggressive invasive species, the costs pale in comparison. It is true that common foxglove is not a native plant.

However, it does not outcompete native plants on the same magnitude that many other noxious weeds do. Foxglove provides resources for pollinating insects and possibly helps maintain natural environments as well. After all, every inch of land currently occupied by foxglove is one less inch of land available land for the establishment of another invasive. 

Perhaps, out of all the invasive plants restorationists must deal without in the field, foxglove is simply the lesser evil.