The Invasive Plant Issue

Euonymus alatus compactus in 5Rivers Metroparks near Dayton, Ohio

The invasive plant issue is not going away any time soon. While some industry professionals are sensitive to this horticultural product liability issue, others are hiding under a burning bush, hoping it will all blow over. Massachusetts and some other states have already banned a plethora of nursery production plants, including burning bush, Japanese barberry and Norway maple. Other states, like Connecticut, use the same assessment protocol, which is endorsed by the American Landscape and Nursery Association (ANLA), and put many of the same plants on a list. These states then work with the nursery industry to determine what to do with the plants.

Ohio is the most recent state to develop an assessment protocol and related procedures to evaluate invasive plants. The Ohio Invasive Plants Council spent four years on the project, working with other stakeholder groups such as the Ohio Department of Natural Resources, The Nature Conservancy and Ohio Nursery and Landscape Association (ONLA), to create a 22-question, science-based tool to generate a new official list of invasive plants. Many of the same nursery production plants as in Massachusetts and Connecticut may end up on the list over the next couple years.

The Ohio process will concurrently address nursery cultivars and a separate list of alternative plants, which will include native plants, as well as non-native, non-invasive plants. The five-person assessment team responsible for addressing these issues includes two horticultural researchers designated by ONLA. Potential regulation of invasive plants, however, remains to be addressed in Ohio.

What Invasive Means

When it comes to defining what an invasive plant is, there tends to be confusion. Some growers may ask, “Don’t we all want plants that are somewhat aggressive and tenacious? Isn’t that what we refer to as garden performance?”

Think of it this way: We’ve all seen weeds that proliferate in our nurseries and greenhouses. They form monocultures in our fields, containers and non-crop areas, and we spend big-bucks preventing or removing them. We’ve also seen pests and pathogens like Asian longhorned beetle, emerald ash borer and boxwood blight invade our region with huge potential impacts. Likewise, invasive plants have the potential of taking over natural areas like parks, forests and preserves. These are not to be confused with the “garden thugs” that disrupt our cultivated areas. There is a difference between weediness and invasiveness.  
In order to be considered invasive, a plant must:

1. Jump over some form of spatial gap to escape from cultivation or initial infestation
2. Invade a natural area
3. Reproduce in the natural area
4. Expand its foothold over time.

The bar is set fairly high, which is why most non-native horticultural introductions are considered non-invasive.  

Why Invasive Is Problematic

Why should we care if a plant takes over a natural area? The easy solution is to pull them or simply let them go. Isn’t this part of a grand process called nature? Isn’t the movement of invasive plants around the globe part of a natural process? We just happen to accelerate it a little with our collecting and breeding. It may even seem as if we’re making our world better.

The answer lies in the importance of biodiversity to our local ecologies. When a plant takes over a natural area and creates a monoculture, it tends to sterilize the environment. Natural systems that have evolved over millennia will no longer function. Research shows these new arrivals take a minimum of 500 years — often much longer — to evolve into hard-working ecological citizens. Eventually these natural systems stop working, and the constructive interactions between plants, insects, birds, beneficial fungi, nutrients and countless other factors are affected.

For example, according to Douglas Tallamy’s Taking Nature Home, non-native bush honeysuckles are rapidly becoming The Shrubs That Ate Southern Ohio. This occurred in less than fifty years — the ecological blink of an eye. Common reed (Phragmites australis) has accomplished the same feat in Northern Ohio.

Common reed was not introduced by the nursery industry, but other plants, such as Asian bittersweet, demonstrate a similar potential. Research shows non-native plants take an average of 125 years to demonstrate invasive potential, but Japanese honeysuckle remained in-bounds only for about 80 years before leaping from cultivated areas into the woods. All of these plants have had a tremendous negative impact on the natural ecosystem they invaded.

Stopping The Spread Of Invasives

We call ourselves the green industry. As conscientious stewards, shouldn’t we guard the doorway between cultivated and natural areas? The Voluntary Codes of Conduct for Nursery Professionals adopted by ANLA, ONLA and others in 2002 resolved to “ensure that invasive potential is assessed prior to introducing and marketing plant species new to North America [and] phase out existing stocks of invasive species.”

Ten years later, there is still a lot of work to do. Why not evaluate invasive potential of perennials and shrubs in connection with our nationwide plant trials? When clear and convincing evidence exists on plants in the trade, such as Lythrum virgatum ‘Morden’s Pink’ and ‘Morden’s Gleam,’ why not voluntarily remove them from production? With so many great under-used plants on our palette, we can avoid over-reliance on so few. Non-invasive alternatives to common nursery plants represent a profitable value-added product. Now, think about how can we encourage our research partners and plant breeders to develop them faster.                                            

Leave a Reply

2 comments on “The Invasive Plant Issue

  1. So great to read such a forward thinking article! As a young, freshly minted grower I am often disappointed with the lack of "green" in our "green" industry. We must learn how to translate green (sustainable products) into green ($) – afterall, the tides of economics and the environment are changing – learn and change now, or fall behind.

More From Varieties...
Penn State University Trial Day

August 26, 2016

How Greenhouse Growers Can Broaden Their Horizons

Allan Armitage says you can learn new ideas to help your business when you get out to visit plant trials and other growers.

Read More

August 23, 2016

Kick Spring Sales Up A Notch With 18 New Plant Introductions For 2017

It’s time to look forward to the spring season and what plants will get your business off to the right start. These 18 new cultivars have all the traits of good breeding — uniform habits, bold colors, showy blooms, good vigor, and excellent branching.

Read More

August 23, 2016

Gardens Alive! Parent Company Buys Zelenka Farms

  Zelenka Farms, which has been in Chapter 11 bankruptcy, says LM Farms, which owns Gardens Alive!, has purchased the company and all of its assets. BFN Operations LLC and its affiliated entities, d/b/a Zelenka Farms, operated one of the largest wholesale nurseries in the U.S. Its products include shrubs, trees, perennials, roses, and groundcovers. The owners of Gardens Alive! have successfully purchased several other companies from bankruptcy and are experienced nursery managers. Niles Kinerk, Chairman of LM Farms, stated that “the opportunity to purchase Zelenka Farms assets and to continue the turnaround that is well underway is exactly the kind of opportunity that we look for. We understand the efforts of the management team led by Eric Ek and others have been successful, and we will support the management team in the coming months and years.” Zelenka Farms operates its six facilities across the key growing regions in the […]

Read More
Latest Stories
Penn State University Trial Day

August 26, 2016

How Greenhouse Growers Can Broaden Their Horizons

Allan Armitage says you can learn new ideas to help your business when you get out to visit plant trials and other growers.

Read More

August 23, 2016

Kick Spring Sales Up A Notch With 18 New Plant Introduc…

It’s time to look forward to the spring season and what plants will get your business off to the right start. These 18 new cultivars have all the traits of good breeding — uniform habits, bold colors, showy blooms, good vigor, and excellent branching.

Read More

August 23, 2016

Gardens Alive! Parent Company Buys Zelenka Farms

  Zelenka Farms, which has been in Chapter 11 bankruptcy, says LM Farms, which owns Gardens Alive!, has purchased the company and all of its assets. BFN Operations LLC and its affiliated entities, d/b/a Zelenka Farms, operated one of the largest wholesale nurseries in the U.S. Its products include shrubs, trees, perennials, roses, and groundcovers. The owners of Gardens Alive! have successfully purchased several other companies from bankruptcy and are experienced nursery managers. Niles Kinerk, Chairman of LM Farms, stated that “the opportunity to purchase Zelenka Farms assets and to continue the turnaround that is well underway is exactly the kind of opportunity that we look for. We understand the efforts of the management team led by Eric Ek and others have been successful, and we will support the management team in the coming months and years.” Zelenka Farms operates its six facilities across the key growing regions in the […]

Read More
Coreopsis-UpTickCream-19793-DarwinPerennials

August 20, 2016

Growing Tips On Coreopsis UpTick Series From John Wilso…

Editor’s Note: In this new feature, the Greenhouse Grower varieties team will choose one noteworthy variety each month we think is worth bringing to your attention. Then we’ll share growers’ and breeders’ perspectives on the best ways to produce it successfully at your operation. This month we focus on the hardy Coreopsis UpTick series, winner of Greenhouse Grower’s 2016 Industry’s Choice Medal of Excellence for Breeding. Growing Tips From John Wilson, Seville Farms When asked about producing Coreopsis UpTick, John Wilson says he doesn’t have much to say because it was so easy to grow. Wilson, a Corporate Grower for Seville Farms, says based on the new series’ strong performance during the trialing he has done so far, the nursery ordered a large quantity of the plants for future growing. “If breeders were looking to come up with something that says ‘wow,’ they have done it with the UpTick Series,” […]

Read More
Eucomis arrangement from Golden State Bulb

August 19, 2016

What’s New With Blooming Potted Plants

From exotic orchids and lilies to flashy red cyclamen and jaunty gerberas, new blooming potted plants come in every shape, size, and color.

Read More
Craspedia Golf Ball Beauty (Danziger)

August 19, 2016

Learn How Unconventional Plants Can Be Hidden Gems

According to Kelly Norris, plant breeding inspired by consumer motivations and interests restores our connection with consumers thirsty for out-of-the-ordinary plants.

Read More
Petunia 'Moonstruck' (2015 Welby Gardens Field Trials)

August 9, 2016

Welby Gardens Names Top Selections From Its Trial Garde…

Welby Gardens, an exclusive grower of Hardy Boy Plants, tested more than 900 varieties this year in its field and container trials. Find out which varieties were the cream of the crop.

Read More

August 6, 2016

Growing Tips On Petunia ‘Night Sky’ From Da…

Production tips for Petunia ‘Night Sky’ from Dan Chaney, Vice President of Production, at Ivy Acres.

Read More
Janeen Wright

August 5, 2016

Deliver Plant Performance As Promised

It would be ludicrous to promise more than you can deliver. But you can deliver more than you promise to your greenhouse customers.

Read More
OSU 2016 In-Ground trials

August 2, 2016

Ohio State University 2016 Plant Trials Offer Real-Time…

The Ohio State University (OSU) displayed more than 500 cultivars for evaluation this year at the Chadwick Arboretum and Learning Gardens in Columbus, OH. Several Cultivate'16 attendees took the opportunity to wander the trial grounds and evaluate in-ground entries and those in sun and shade containers and hanging baskets.

Read More
Bellis Speedster (Benary)

August 2, 2016

How Fall Can Be About More Than Pansies

Allan Armitage suggests a few notable plants for the fall shoulder, fall sales, and spring shoulder seasons.

Read More
Petunia 'Amore Queen of Hearts' from Danziger

August 1, 2016

Danziger Targets Future Growth With Recent Management C…

The changes will provide a foundation of growth, creativity, and innovation, notes Micha Danziger, who will now serve as chairman of the Board of Directors.

Read More
Griffin 2017 Seed and Plant catalog

July 31, 2016

Griffin 2017 Plant Catalog Now Available In Print And D…

The print catalog features more than 280 new varieties, while the digital edition has several bonus resources.

Read More
Westhoff-Florist Holland combos

July 30, 2016

Pair New Spring Crops With Fresh Ideas For Increased Sa…

There are plenty of exciting, new spring crops to consider incorporating into your crop selection. What will set your operation apart is how creative you are about what plants you select, and how you promote them.

Read More
Pleasant View Gardens Savor Edibles

July 22, 2016

Pleasant View Gardens Targets Millennials With Savor Ed…

Taking something as ubiquitous as vegetables and herbs and giving it a fresh new look is no easy task, but Pleasant View Gardens took on the challenge with extensive research and creative marketing.

Read More
Dummen New Columbus Office

July 21, 2016

Dümmen Orange Opens New North American Headquarters In …

The new office, which officially opened during Cultivate’16, supports the company’s vision to be integrated into a vibrant and inspiring community, and provides a bright, modern workspace for its approximately 30 local employees.

Read More
Pollen Free Lisianthus

July 20, 2016

Sakata Seed Develops World’s First Pollen-Free Lisianth…

With no stamen to produce pollen, the new Lisianthus varieties have improved flower durability and the benefit of no scattered pollen that can cause staining of flowers and machines.

Read More

July 19, 2016

17 New Vegetable Intros For Greenhouse Production

New varieties of edibles introduced at 2016 California Spring Trials offer something for every type of gardener, from the beginning do-it-yourselfer to the hardcore, heirloom-only type. Check out some of the new varieties we saw at Spring Trials this year that will be available for retail in 2017.

Read More
[gravityform id="35" title="false" description="false"]