One of the questions that came up concerned the risks, if any, to wild populations of native plants are presented when cultivated plants are introduced into the landscape.
In the absence of robust and reproducible evidence that address this concern head on, practitioners are often forced to rely on aphorisms.
“First, do no harm.”
“If it ain’t broke, don’t fix it.”
“The perfect is the enemy of the good.”
And often, native plant enthusiasts will invoke the precautionary principle.
Though it has many definitions, I think the most sensible one is Wingspread version: “”When an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.”
Although this principle is more often used in discussions about pesticides and GMOs, I’ve seen it used to warn against the alleged dangers of using native plant cultivars. When explicitly stated, these dangers usually involve some kind of worry about genetic pollution or contamination of wild populations.
As I mentioned earlier, there is virtually no evidence that native plant cultivars have, can, or will negatively affect the genetic diversity of wild populations. But the precautionary principle is used to suggest that we should not use such cultivars “just in case”.
It is worth mentioning, however, that the precautionary principle is not universally beloved. At best the principle is ambiguous. At worst, it is – itself – hazardous.
As the Social Issues Research Centre notes:
In itself the precautionary principle sounds harmless enough. We all have the right to be protected against unscrupulous applications of late twentieth century scientific advances – especially those which threaten our environment and our lives. But the principle goes much further than seeking to protect us from known or suspected risks. It argues that we should also refrain from developments which have no demonstrable risks, or which have risks that are so small that they are outweighed, empirically, by the potential benefits that would result. In the most recent application of the doctrine it is proposed that innovation should be prevented even when there is just a perception of a risk among some unspecified people.
It would appear that the opposite of precaution is carelessness, and who could be for that?
But, as we’ve seen often, inaction is sometimes more dangerous than action. If acting out of an abundance of caution keeps us on a path of inaction, to the detriment of the ecological health of our gardens and landscapes, have we really achieved what we desire?
‘Better safe than sorry’ isn’t always safer. In fact, when it comes to policies to protect public health and the environment, this type of thinking could harm us. – American Enterprise Insittue
At the workshop on Wednesday, Annie White presented evidence from her five-year study of pollinator interactions on cultivars of native plants. In almost half the cases she studied, the cultivar attracted as many or more pollinators than the straight-species. At trials in the gardens of Penn State, the cultivar was better than or equal to the species in pollinator attractiveness in more than half the cases.
In a world that is being revegetated and dominated by non-native monocultures, is a garden full of Penstemon digitalis ‘Husker Red’ truly more dangerous to the earth than the same garden full of hosta?
When ecologists work with large scale restorations, or with tiny and isolated populations of endangered plants, I definitely see the value in taking actions that minimize the risk to the genetic diversity of surrounding wild populations.
But everything we DO know about plant population genetics tells us that, generally, cultivars present little risk to our ecosystems. At the same time, we have voluminous evidence that these ecosystems benefit from a greater proportion of native plants.
So, if you visit your local garden center and the only bee balm they have is Monarda fistulosa ‘Claire Grace’ then please throw precaution to the wind and buy it.