It occurred to me recently – in looking at a St. John’s Wort blooming in our upper meadow, and contemplating its place here – that we use the term “naturalized” to describe both human and plant immigrants – or those who are not native to our part of the planet, but have adapted in ways that make it like a native. Oxeye daisies are one of my favorite European immigrants that has naturalized in many parts of North America.
We tend to further categorize both human and plant/animal/insect immigrants. There are those naturalized ones that we call invasive because they have done so well in their new home that they become the dominant species in some areas – crowding out the native species (the early European settlers of North and South America and Australia are good examples of human “invasives” that moved in and pushed out the natives of the area).
Many of the plants we consider “weeds” were brought here by human settlers who valued them enough to want them in their new home. Many were edibles or medicinal herbs – like the St. Johns Wort in front of me, or were favorite flowers like the daisies I have grown all around my orchard.
I began questioning the thinking around “weeds” and invasives when I noticed, about 9 yrs ago, that there were a number of false dandelions or flatweed (Hypochaeris radicata) – a dandelion flower look-alike that is also edible – growing in the area where my pond is now. This area was unusually devoid of ground covering plants when we moved here. Nothing seemed to grow there, except a few native trees. I had a feeling that something toxic may have been done here and determined never to grow food or medicinal plants in this area.
Then – a year or so later – I began to notice false dandelions sprouting up here and there. Bit by bit over the years more plants moved in along with the dandelion look-alike. Most of these plants were also non-native “weeds” – the sorts of plants that usually move into “disturbed” soil. I noticed that false dandelion is the plant invariably seen in vacant lots and untended/unwatered “lawns” and any place where the conditions are poor. It’s as though they are the “first responders” for mistreated or damaged soil. Perhaps their tough roots break up hardpan or they mine nutrients from deeper in the soil or perhaps they have the ability to detoxify the soil in some way. I don’t know. But now that area has a thick layer of nice healthy plants growing all around the pond I put in 3 yrs. ago – thanks, I’m sure, to the work of the false dandelion and the “weeds” that followed.
I noticed a similar “first responder” effect in the clearings left by the logging done in my little woodland a few years before we moved here. Another “foreign invader” – Scotch Broom – came up in all the cleared areas. It’s a legume – so it is a nitrogen fixer and perhaps its long tap root also breaks up the hardpan caused by logging equipment. I’m not sure. It also provides some cover for the native seedlings that sprout around it. And – like the false dandelion – it is a favorite pollinator food when it blooms in spring. However in some situations it will outgrow and compete with native seedlings and in fire country it is a very flammable plant, so I don’t let it grow more than a couple feet tall before I cut it out.
Stephen Harrod Buhner talks about “invasives” a bit in his latest book, Plant Intelligence and the Imaginal Realm. He suggests we ask ourselves “why are they here”?
The Himalayan blackberry – the bane of many a Pacific Northwesterners existence – is a plant we have a love-hate relationship with. The berries are big and sweet and delicious – even more so than most cultivated berries. They demand no special care (except staying away from their thorns when you are picking!), feed many pollinators when they flower and many types of animals and insects when they fruit. My old dog Ginger used to love eating them while she patiently waited for me to fill my bucket, and I have seen coyote/ raccoon and possum scat colored purple and filled with their seeds. And just like Br’er Rabbit’s famous Briar Patch – they provide habitat and safety to many creatures I’m sure. Unfortunately they are painfully thorny, and hugely rambunctious in their growth and seeded around prolifically by all the creatures who eat the berries!
As I mentioned, many of our invasive naturalized non-natives were brought here because of some quality or characteristic that was seen as useful by humans. The Soil Conservation District is responsible for introducing some of our most challenging ones – like the famous Kudzu vine of the south (it really can cover houses and tall trees – I lived around it for a few years)! There were actually Kudzu clubs in the early 1940’s.
Many are edible and/or medicinal and many are beautiful in some way – like yellow flag iris and purple loosestrife – and so – even though they are on many invasive species lists – people continue to plant them. Just like the immigrants who are the cause of so much contention. Even though they are “illegal” they are encouraged and invited in by those who find them useful in some way.
Occasionally – like the European immigrants who came to North America and Australia so long ago – non-natives will thrive and flourish and do so well that they crowd out the natives. This creates an imbalance and reduces diversity, one of the strongest components to resilience. These instances are sometimes dramatic – as with kudzu in the South and waterways clogged with water hyacinth from the Amazon.
However, the vast majority of naturalized non-natives live among us and blend in, providing benefits we often do not notice or acknowledge. Humans, plants and other animals have been moving around the planet for ever, I think. It seems a natural part of the flow of nature. We are so focused on the small picture – on our tiny human time frame – that we don’t see how, given time, Nature inevitably balances things out and never stops changing.