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...
Coleus Fancy Feathers Pink (Terra Nova Nurseries)

May 23, 2016

Take A Sneak Peek at Terra Nova Nurseries’ New Coleus Fancy Feather Series

A brand-new collection of Terra Nova Nurseries coleus varieties called the Fancy Feathers Series is now available to growers for online orders. The series produces narrow, feather-like leaves and offers a mounded habit.

Read More
Rotary Botanical Gardens, Wisconsin

May 16, 2016

All-America Selections Summer Summit In Madison, WI, Will Offer Display Garden Tours And Much More

Registration is now open for the 2016 Summer Summit, which takes place in August and features a focus on the locally grown movement.

Read More

May 10, 2016

13 New Native Plants And Nativars For Going Green [Slideshow]

Native plants are becoming a bigger part of living green, as consumers become more aware of the role regional native plants play in promoting biodiversity in the garden, in urban landscapes, and in habitat restoration. Here are 13 new native plants breeders are offering to consider for your product mix.

Read More
Latest Stories
Coleus Fancy Feathers Pink (Terra Nova Nurseries)

May 23, 2016

Take A Sneak Peek at Terra Nova Nurseries’ New Coleus F…

A brand-new collection of Terra Nova Nurseries coleus varieties called the Fancy Feathers Series is now available to growers for online orders. The series produces narrow, feather-like leaves and offers a mounded habit.

Read More
Rotary Botanical Gardens, Wisconsin

May 16, 2016

All-America Selections Summer Summit In Madison, WI, Wi…

Registration is now open for the 2016 Summer Summit, which takes place in August and features a focus on the locally grown movement.

Read More

May 10, 2016

13 New Native Plants And Nativars For Going Green [Slid…

Native plants are becoming a bigger part of living green, as consumers become more aware of the role regional native plants play in promoting biodiversity in the garden, in urban landscapes, and in habitat restoration. Here are 13 new native plants breeders are offering to consider for your product mix.

Read More
Pennisetum alopecuroides ‘Ginger Love’ (Aris Greenleaf Plants)

May 10, 2016

12 New Ornamental Grasses For Low Maintenance Garden Ap…

Nothing says low maintenance like ornamental grasses. They add texture, movement, and all-season color to the garden. Check out 12 new ornamental grasses and grass-like varieties for growing in your greenhouse or the garden.

Read More
Blueberry ‘BrazelBerries Perpetua’ (Fall Creek Farm & Nursery)

May 9, 2016

Why Star Roses And Plants Is Buying The BrazelBerries P…

The purchase includes the brand, variety portfolio, and grower network, and allows Star Roses to capitalize on increased berry consumption among consumers.

Read More
Wave Petunias Team

May 3, 2016

Hot Pink Wave-Rave Van Making Its Way To The Big Apple …

Imagine driving down the road, minding your own business, when you’re passed by two smiling, waving, happy women driving a hot-pink van that’s adorned with petunia and pansy flowers. That’s not something you see every day, but motorists in the Midwest and Northeast may catch a glimpse of the Wave-Rave van this week as Ball Horticultural Co.’s Claire Watson, Product Marketing Manager, and Katie Rotella, Marketing Communications Manager, make their way to a media tour and plant giveaway in New York City. Watson and Rotella visited Cleveland’s WOIO Channel 19 news on Tuesday morning to tell consumers about Wave Petunias and Wave Pansies, and remind them to visit their local garden centers to purchase gifts for Mother’s Day this weekend. Check out this clip on Periscope. After the morning news, the ladies stopped by to visit the Greenhouse Grower staff at Meister Media Worldwide in Willoughby, OH. Next stop: Chelsea Garden Center in Brooklyn, NY, where […]

Read More
National Garden Bureau CAST 2016 Bloggers

May 3, 2016

5 Things Gardens Bloggers And Writers Learned At Califo…

For the second year in a row, the National Garden Bureau hosted five popular garden bloggers and writers on a trip to California Spring Trials. Here’s what each of them had to say about their experience.

Read More
Chick Charms

April 29, 2016

Kelly Norris: Why The Plant Collector Market Is Set To …

In his latest column for Greenhouse Grower magazine, Kelly Norris says there are more plant collectors out there than we think, which opens the way for the gift plant market to explode.

Read More
Pennisetum Fireworks

April 28, 2016

Why Ornamental Grasses Are Great For People In Condos A…

Allan Armitage says breeders need to do a better job of making growers, brokers, and garden centers aware of better ornamental grass cultivars for the increasingly shrinking garden space.

Read More
Andropogon gerardii Blackhawks (Intrinsic Perennial Gardens)

April 27, 2016

Know Your Market When Choosing Ornamental Grasses

Growers have no shortage of choices in the ornamental grass market. Narrowing down the selection comes down to finding the right plant for the right purpose.

Read More
Bee on Bidens

April 25, 2016

Breeders Go The Distance To Bring New Plant Varieties T…

Breeders are meeting the demand for new varieties that perform and sell well by extending trialing to engage the grower community, using advanced technology, and encouraging international collaboration.

Read More
Dr Allan Armitage

April 20, 2016

Growers And Breeders Are Always Looking For A Better To…

While edibles become more diverse, there's one goal that hard-core gardeners and urban foodscapers share.

Read More
Syngenta Pentas

April 20, 2016

Syngenta Flowers Opens Its Perennial Genetics To The Ma…

California Spring Trials 2016 visitors to Syngenta Flowers found the breeder company and its employees happy and excited for the future, in the wake of the announcement of its acquisition by ChemChina. Now Syngenta Flowers is ready to move forward with its breeding efforts in geraniums, pentas, and other crops, and it is opening its perennials offerings to the whole supply chain for a better chance to get those plants to retail.     Syngenta Wants To Revolutionize Geranium Breeding The big news in this year’s trial, says Karl Trellinger, Technical Services Representative at Syngenta, is the change in Syngenta’s breeding efforts in geraniums and pentas. The Calliope geranium series, long considered a premium line in the market, is getting a makeover. Growers have told the breeder that they love the colors available in the Calliope series, but the plants are just too vigorous for smaller containers and combinations. As […]

Read More
Petunia Vista Bubblegum (Proven Winners)

April 20, 2016

Proven Winners Funds Gardening “It Couple,” Names Plant…

Since 1992, Proven Winners has been changing the gardening game, and it’s not stopping now. With new plants, improved series, and interesting retail customers, the brand aims to make planning easier for growers, and make gardening easier and more fun for consumers. At its new 2016 California Spring Trials location at Kirigin Cellars in Gilroy, Proven Winners had the space and a beautiful setting to lay all of its offerings out, from new and improved varieties in annuals, perennials, and shrubs, to marketing and retail programs. Check out the slideshow below for highlights.   Proven Winners Is Flexing Its Marketing Muscle One of the ways Proven Winners is working toward better use of its products and gardening in general, is by supporting the gardening authorities that gardeners of all ages trust on social media. Director of Marketing Marshall Dirks says while searching for influential gardeners, he came across a young […]

Read More
Scaevola 'Purple Haze' (Danziger 2016)

April 19, 2016

Allan Armitage Picks His Favorites From Proven Winners,…

From “crazy” petunias to container pentas, there was plenty that caught Allan’s eye during the final day of 2016 California Spring Trials.

Read More
CallaFornia Red

April 19, 2016

Golden State Bulb Company Shows Off New Concepts In Cal…

There’s no question that Golden State Bulb Company’s specialty is in breeding virtually any color of Calla Lily, available in about any habit — cut flower, bouquet pot, upright pot type — the list goes on. But now, the bulb specialist is focusing on making calla lilies more accessible to the masses, for use in combination planters and the landscape, with calla six-packs. Calla breeder Peter Beckman showed us the shrunken-down version of these beauties, and they’re certainly perfect for patio pots, planting along paths or at the front of the garden, or en masse for an elegant statement. This presentation makes it easy for consumers to pick up and use callas, without the intimidation they might feel from a bulb crop, says Dr. Allan Armitage.   They’re also versatile for growers to plant in early to mid-February to add to finished containers in the spring, or to sell in […]

Read More
Disney Trial Garden

April 17, 2016

Mark Your Calendars For Florida Flower Trials In May

The two-day event, which takes place in Orlando, is held in conjunction with the Epcot International Flower and Garden Festival and offers educational seminars, tours, and open houses.

Read More
Dianthus Paint the Town Fuchsia_CJW14 (2)

April 16, 2016

Proven Winners Focuses On A Better Consumer Garden Expe…

Excellent, long-lasting performance, and easy maintenance are at the core of Proven Winners’ introductions.

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