No matter how you feel about the issue of invasive ornamental plants, it’s clearly of economic importance to nursery professionals. Retail buyers respond to advertising, and the industry responds to demand by the public.

“We offer what people want to buy,” is an often-heard comment from growers. But I feel this is a shallow rationale for the failure of some nursery operators to make a principled value decision to quit shipping plants that have been demonstrated by science-based risk assessments to be invasive.

As an industry, and individually as nursery growers, we must all take responsibility to stop growing invasive plants.

Definitions

What defines a plant as truly invasive, instead of merely aggressive or what some call a “nuisance”? We have too many definitions and too little consensus.

Yet, widely accepted definitions were offered in President Clinton’s Executive Order 13112 on Invasive Plants, dated February 1999:

“‘Invasive species’ means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.

“‘Alien species’ means, with respect to a particular ecosystem, any species, including its seeds, eggs, spores or other biological material capable of propagating that species, that is not native to that ecosystem.”

Even these definitions muddle the issues. Discussions that link invasive ornamental plants and native plants almost always end up dysfunctional. In Oregon Association of Nurseries discussions with a wide variety of stakeholders, I’ve found that by separating the issues of natives and invasives, we’re able to find common ground fairly quickly.

The overwhelming majority of “alien” introduced species are not invasive. They enhance our constructed landscapes across the seasons. Can you imagine our gardens without the many wonderful cultivars of Cornus kousa?

Aliens are necessary

Contrast its relatively disease-free character with that of our own native flowering dogwood, Cornus florida or Cornus nuttallii. While native plants are desirable for their many environmental benefits, including promoting pollinator diversity and wildlife habitat, our common sense guides all of us to the conclusion that native plants are not always the best choice for a given site. This is especially true when you consider the radically different character of constructed sites versus nearby wild landscape. Our industry would not exist without essential introduced plants.

Natives, despite what some passionately advocate, are not a solution to the invasive plant conundrum. They are no panacea. Low maintenance? Ask a landscape foreman.

To maintain an exclusively native landscape, it may require more attention (cost) than a balanced mix of native and non-native plants. To rebalance the portfolio of least-input choices, we may select relatively more native plants in the future, but it will be a mix of introduced and native plants that give maximum benefits in constructed urban and suburban landscapes.

So I reject the whimsical notion that the solution to the very real economic damage caused by invasives will be solved by substituting only native plants. That is neither feasible, nor wise. We can’t go backward 250 years, but we must responsibly move forward.

Costs of invasives

An unadorned, ugly fact remains: The environmental costs of invasive plants are enormous.

A well-documented study of the costs of invasive species was published by Cornell University in June 1999. According to the research, purple loosestrife (Lythrum salicaria) -- introduced by the nursery industry and still propagated in the trade by a few poorly informed growers -- now spreads at the rate of 287,000 acres per year.

It’s changing the basic structure of the wetlands it invades. It out-competes wetland plants and endangers wildlife that depends on such plants.

Purple loosestrife now occurs in 48 states and costs $45 million per year in control expenses and forage losses.

Cornell also reports that in Great Smoky Mountains National Park, 400 of the approximately 1,500 vascular plant species present are exotic. Ten of these are displacing and threatening other species. In Hawaii, the problem is magnitudes worse.

Other industries have been forced into accountability via restrictive legislation or litigation. Clearly the press coverage of such controversies is negative for nursery professionals.

It’s easier to demonstrate responsible leadership and to solve our own problems than to oppose or try to repeal ill-conceived legislation. We must act now to avert these burdens.

We have our heads in the sand if we think this problem will be resolved by state lawmakers. We must look at profit opportunities as the mechanism to create a new dialogue focused on removing offensive plants from propagation by substituting alternatives that may offer increased profit opportunity.

Voluntary codes

This issue is complex. It’s not as straightforward as the fundamental value judgments that motivate us to not propagate invasive ornamentals.

We must own this issue based on our core values, within guidelines now well-established by the voluntary “Codes of Conduct for the Nursery Industry.” In our positions of influence, we have the opportunity to effect change, in keeping with the codes.

Although American Nursery & Landscape Association and other state and regional nursery associations have endorsed the codes, these groups don’t sell a single plant. We have an opportunity in our state associations and under committed ANLA leadership to continue to educate our peers on this issue at the state and regional level, to publish definitions, continue dialogue and raise production standards.

Government can’t bring about change in behavior except by new regulation or legislation, perhaps ill conceived. Ask your friends in Connecticut or New Hampshire about the cost of opposing legislative solutions to this problem.

Ask yourself, “Can your own state association effectively oppose legislation or fund court challenges on a shrinking budget?”

Individual commitment

Are we opportunists who irrationally ignore our responsibility to our customers, our cities and society in general by continuing to propagate invasive ornamental plants? Or do we own the professional obligation to quit this offensive practice?

We in the nursery business are prominent stewards of plant diversity and all the natural resources it takes to preserve, protect and enhance them. Shouldn’t we care? If we don’t, what does that express about our stewardship ethics?

If we fail to stop growing invasive plants, what does it say about our character as growers? Is profit our only decision-making motive? The answer is of course not.

At Heritage Seedlings, in addition to asking ourselves if we can make a buck growing a plant, we make the voluntary commitment to pass propagation decisions through an additional filter.

Does this plant pose an invasive problem in our market area? It’s simple but effective.

The impact on our bottom line has been negligible. We’ve received many compliments about our environmental commitment, and have made it very clear in a two-page color spread in our 2004 catalog.

Others have made the public commitment as well, or they have simply and quietly dropped offending taxa.

Acting together

I invite dialogue on this issue at the many venues in which the nursery industry gathers -- trade shows, state, regional and national association meetings. I also call for industry members to make production decisions guided by the voluntary codes.

They are voluntary. Nobody tells you what to do.

You’re guided by your own keen sense of what is right and your profit motive in substituting alternatives. Some firms choose to phase out of production of invasive ornamentals over several years. They have not quit cold turkey.

The codes also call for the industry to recommend and promote alternatives to known invasive plants. Discuss this and other articles on invasive plants with key staff members.

Talk about your core company values and about profit opportunities within your firm’s commitment to the codes. Offering substitutes is potentially more profitable than propagating the invasives.

We are the stewards of our natural resources and our future. Let’s not allow others to take that privilege from us by our own inaction on this critical issue. Timing is everything.

What will you do in 2007 to make a policy commitment within your own firm?

Codes of conduct

In 2001 in St. Louis, a task force including environmentalists and members of the industry developed the voluntary “Codes of Conduct for the Nursery Industry.”

The codes are:

* Ensure that invasive potential is assessed prior to introducing and marketing plant species new to North America. Invasive potential should be assessed by the introducer or qualified experts using emerging risk-assessment methods that consider plant characteristics and prior observations or experience with the plant elsewhere in the world.

Additional insights may be gained through extensive monitoring on the nursery site prior to further distribution.

* Work with regional experts and stakeholders to determine which species in your region are either currently invasive or will become invasive. Identify plants that could be suitable alternatives in your region.

* Develop and promote alternative plant material through plant selection and breeding.

* Where agreement has been reached among nursery associations, government, academia and ecology and conservation organizations, phase out existing stocks of those specific invasive species in regions where they are considered a threat.

* Follow all laws on importation and quarantine of plant materials across political boundaries.

* Encourage customers to use, and garden writers to promote, non-invasive plants.

- Mark Krautmann

 

Mark Krautmann is co-owner of Heritage Seedlings Inc., 4199 75th Ave., S.E., Salem, OR 97301-9242; (503) 585-9835; fax (503) 371-9688; www.heritageseedlings.com.

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