Sustainable Horticulture

Nursery Industry Explores Biodegradable Containers

Posted by sustainable_hort on May 31, 2010  |  No Comments

Plastic containers revolutionized plant production. Now a significant percentage of plants are grown in some type of container. At the retail level, containers not only hold plants and soil, but they have become a visual part of the marketing.

Yet, environmental concerns increased with plastic products, both in how they are made and how they become a waste stream. So, container manufacturers began to look at other materials. The challenge was to find materials that could contain the soil and plants as they moved through the production and marketing system, yet breakdown after they were used, usually in composting systems.

Numerous substrates are being used and tested to create a range of biodegradable pots including waste paper, peat, coir, cornstarch resins, wheat, bamboo, and even cow manure.

Finding plastic replacements for containers has become an important research topic, with the American Nursery and Landscape Association (ANLA) starting research several years ago to identify useful container substrates (see below). The key challenge is finding compounds and resins that, when combined, will stand up to normal environmental pressures.

“We need materials that will stand up to the south’s warmer temperatures, heavy irrigation schedules, and high levels of nitrogen,” explained Agricultural Research Service horticulturist Donna Fare. She said these environmental factors work together to break down non-plastic pots in the field. Fare is heading up the ANLA-sponsored research project in McMinnville, Tennessee, which will finally test a chicken-feather based container during this year’s growing season.

Recycled Plastic a First Option
Many nursery container producers have morphed from using virgin plastic to using recycled materials. This is a major step toward sustainability, since it at least recovers the plastic already in use in the nursery industry, plus absorbing some of the consumer waste stream.
For instance, ITML Horticultural Products Inc. has a line of recycled containers, called Elite and Euro System Nursery Containers, made with “100% recycled, indestructible polyethylene material.”

Another example is the Root Pouch containers from Averna and Associates. These pouches are made from polyethylene terephthalate (PETE), which comes from recycled plastic beverage bottles, which are turned into non-woven fabric. It is used to manufacture a full line of nursery containers including propagation liners and various sizes of plantable pouches, available in different densities and degradable life spans.

Finally there are oxo-biodegradable products, which I have not found yet in the industry. Wikipedia defined the plastic as follows:

“Oxo Biodegradable (OBD) plastic is polyolefin plastic to which has been added very small (catalytic) amounts of metal salts. These catalyze the natural degradation process to speed it up so that the OBD plastic will degrade when subject to environmental conditions to produce to water, carbon dioxide and biomass. The process is shortened from hundreds of years to months for degradation and thereafter biodegradation depends on the micro-organisms in the environment.” I am going to look into this more, so keep reading.

What are Biodegradable Containers?

While there are differences between aerobic and anaerobic degradation, “biodegradable” is usually considered as a material can be broken down into its organic components. Essentially, biodegradable materials avoid increasing landfills by eventually returning them to the soil through effective composting.

As a note, the “effective composting” is a key step to making any of these containers actually biodegradable. In fact, some national and international standards have stricter criteria, defining compostable as having three requirements:

• First, again they must “biodegrade” which is defined as “breaking down into carbon dioxide, water and bio mass.”
• Secondly, they must “disintegrate,” so after three months of composting and subsequent sifting through a 2 mm sieve, there is no more than 10% residue remaining.
• Finally, no “eco toxicity,” so the bio-degradation does not produce any toxic material and the compost can sustain plant growth.

Unfortunately, these global standards exist to certify compostable plastics (ASTM D6400) and compostable packaging (ASTM D6868), under controlled composting conditions typically found only at industrial composting facilities. It is uncertain whether many of these new “plastics” will degrade quickly and effectively in standard landfills or backyard compost bins.

Molded Fiber Early Option

But, many decades ago, molded pulp or fiber first found uses in the horticulture industry. Molded pulp products are made from natural cellulose fibers, including waste papers and peat, and are biodegradable breaking down in compost systems and most landfills. These molded fiber products, were often used in early propagation stages in combination with rigid plastic trays.

But, as plants moved into gallon sizes, most growers continue to use plastic pots, especially if they are shipping plants. The early fiber pots were just not rigid enough to withstand damage during handling.

One of the earlier producers of non-plastic containers was active here in Oregon…Western Pulp Products. The company has more than a 50-year history of making containers using waste paper, collected by charitable organizations (“post-consumer”), while other sources are “pre-consumer,” including Kraft, waxed, and other waste paper. Only the metal rings and hanging wires are not decomposable.

“Even the wax paraffin used to bind the pulp will degrade during composting or in the soil,” said sales manager Jim Lee

While their products are not considered “organic,” they can be used to grow organic plants, according to Lee. He said their growers received approval from Oregon Tilth that organic vegetable transplants can be grown in their molded fiber containers but the plant must be removed from the container before it is planted in the soil. 


Jiffy pots are another decade-old name in nursery containers, entering the market in the mid-1950’s. The George Ball Company bought the U.S. rights from the Norwegian firm that developed the technology. They found numerous uses in nursery propagation, becoming a standard tool for growing plants. But, again, they tended to be too fragile for field and shipping uses.

Wide Range of Substrates Now Available
Many of the newer biodegradable containers are actually manufactured by processes similar to the Western Pulp method…a plant based substrate held together with a binding agent. The choice for substrates continues to expand.

One example are the Fertil biodegradable plant pots, made from 100% natural biodegradable wood fibers, composing 80% of the substrate, plus 20% peat moss. Meanwhile, Summit Plastics Company has a biodegradable line, “Eco 360,” that features containers made of corn, wheat and wood fibers.

Another company, T & R, Woodburn, Oregon, is offering a new line of containers called Ecotainable®. Manufactured by Kelmar’s Creations, the products use ‘patented’ bioresin materials, made from wheat, tapioca, potato starches and corn, to form pots and other products.

CoCo Coir Pot, made by Green Neem, is a biodegradable cultivation pot made of coconut fibers, which have exceptionally high permeability to water, air and roots. Coir products are now available through several companies.

Cow Pots is taking a different approach, using “odor-free, 100% composted cow manure” as the substrate. They claim the manure also adds more nutrition when the plant is growing or transplanted.

Fungi Grows Containers
A radically different approach is the EcoCradle products.
The new product is made from agricultural byproducts including cottonseed hulls, buckwheat hulls and rice husk that are mixed with a filamentous fungi — mycelium — as a bonding agent — and allowed to grow inside molds. The mycelium secretes an enzyme that decomposes the organic waste as it grows. After seven days at room temperature in the dark, a compact, ultra light, malleable material is formed that can resist high temperatures, according to company literature.

Downsides?
While there is an increasing availability of alternative containers, most nurseries have been slow to switch from plastic. Even Northwoods Nursery, Molalla, Oregon, well known for its many sustainable efforts, is still using plastic pots.

“We are just not sure they will hold up over a longer time frame,” said Laura O’Leary, sustainable director for Northwoods. While the nursery has implemented other “sustainable practices,” including recycling plastic containers, they are still holding back on moving to these newer options, she said. Like many nurseries, they plan to test new products, hoping to find products that prove tough.

In addition to needing perfect conditions to decompose, some manufacturers are also cautioning consumers that the pots need to be handle correctly when planting to avoid problems.

For example, Bonnie Plants, uses biodegradable pots extensively, with the smaller versions made by Jiffy. They listed the following rules for using their pots:
• To ensure success, drench the pots thoroughly just before planting.
• Remove the shrink-wrap label from the rim of the pot by cutting it with scissors.
• Also tear away the top of the pot so that the rim is not exposed above ground after planting. If the pot dries out, it can rob moisture from the roots when capillary action pulls water up to the dry rim.
• Finally, tear away the bottom half of the pot before placing the plant in its hole to exposes some roots to direct contact with the soil.

Like any new technology, biodegradable containers will need further refinement and testing to create products that growers will use confidently, especially if plants are shipped.

While there are ongoing research projects (see above) testing how well plants grow in these non-plastic choices, work done over a decade ago showed that plants would grow as well, or better, in biodegradable pots. So, it seems that chief concern remains durability. Once that is solved, biodegradable products could have a bright future in the nursery industry.

You can continue to follow this topic here. I am convinced that we will find more and more organic “waste” products that can be turned into various compostable or plantable pots and containers. Ultimately, they will prove their economic advantage.

Show Me the Research – Glyphosate and GM Problems Expand

Posted by sustainable_hort on May 24, 2010  |  No Comments

Monsanto’s PR team must be up nights…since the good news just keeps coming up around GM technology and their popular herbicide product…Round-Up. We have discussed several resistance issues recently (see both earlier “Show Me the Research” posts), but the concerns and problems are expanding.

First, Round-Up’s affects on plant health.
Microbiologist Robert Kremer USDA-ARS (US Department of Agriculture- Agricultural Research Service) was interviewed recently in the online “The Organic & Non-GM Report,” where he explained his concerns with glyphosate’s (Round-Up) impact on plant health. He was quoted as saying the compound “This system is altering the whole soil biology.” He expanded the observations, noting that “glyphosate can have toxic effects on microorganisms and can stimulate them to germinate spores and colonize root systems. Other researchers are showing that glyphosate can immobilize manganese, an essential plant micronutrient.”

In this month’s issue, the editors interviewed retired Purdue University Emeritus Professor of Plant Pathology, Dr. Don Huber. He said that glyphosate can “significantly increase the severity of various plant diseases, impair plant defense to pathogens and diseases, and immobilize soil and plant nutrients rendering them unavailable for plant use.” And that glyphosate stimulates the growth of fungi and enhances the virulence of pathogens such as Fusarium and “can have serious consequences for sustainable production of a wide range of susceptible crops.”

This all builds on an important work I have written about before…”Healthy Crops, A New Agricultural Revolution” by Francis Chaboussou. In it, he looks at 75 years of similar research on not just glyphosate, but many pesticides, herbicides and nitrogen-heavy fertilizers, and their negative impacts on disease and pest problems. I felt he showed clearly that while the compounds might solve a problem, they usually created others. Others that then required spraying of toxic compounds, which have the same affect. And the circle goes ‘round and the grower pays. Less toxic approaches might actually reduce other input costs…it at least deserves a closer, open-minded look.

GM Bt Cotton Causes Pest Explosion
And then, from China comes a report about a recent disaster that resulted from planting Bt cotton. Bt (Bacillus thuringiensis) is one of best know “natural” insecticides, with the organism successfully controlling several pest outbreaks (various caterpillars). Then, it was inserted genetically into crops, including cotton, where it offered bollworm control. And that part of the equation worked, so growers could stop spraying toxic chemicals. Looked like a win-win.

But then, the fields became infested with another pest, the Mirid Bug, causing serious damage. Scientists determined that the June spraying for bollworms had also knocked back the entire insect community, including other pest species and their natural predators. With no controls, in this case, the Mirid Bug won the race, finding a vast, rich food source, and quickly expanding its populations. It has even moved into other crops such as apples, strawberries, pears, peaches and vegetables, where it had never been a problem. All this started following the switch to Bt crops in 1997, showing up first in cotton in 2000, and moving to other crops by 2005. It seems their only short-term answer is go back to spraying, after paying more the Bt-cotton.

So, again unintended consequences. The GM technology still holds promise to help with world nutrition. The idea and reality of foods that create extra vitamins (improved rice variety) with the help of added genetic information could save lives. But, first it is caution with this new “tool.” It needs more study, more testing in the complexity of an environmental system, to understand those consequences. From these latest reports, it seems to solve single problems only to create others. Not a sustainable system.

For more:
• “Scientist warns of dire consequences with widespread use of glyphosate”, The Organic & Non-GMO Report, May 2010, @ http://www.non-gmoreport.com/articles/may10/consequenceso_widespread_glyphosate_use.php

• “Scientist finding many negative impacts of Roundup Ready GM crops, USDA doesn’t want to publicize studies showing negative impact2, The Organic & Non-GMO Report, January 2010, @ http://www.non-gmoreport.com/articles/jan10/scientists_find_negative_impacts_of_GM_crops.php

Show Me the Research – Volcanoes & Monsanto

Posted by sustainable_hort on April 27, 2010  |  1 Comment

Dear Readers…Sorry about the long break between posts, but farming requires one to take advantage of weather breaks…we finally had a break from several weeks of rain, tilling and planting had to get done.

But, I am back at the desk and this is the first of several posts that will go up over the next few days. The first section here is not really research but I do want to point out actual, current phenomenon that relate to this theory of sustainability. These entries are clarifying examples of why we need, and may be forced, to do things differently when it comes growing and consuming food.

Gaia Gets Back or Free Fertilizer?
First, the Iceland volcano situation. I started college many decades ago in geology and it remains a reference point for me when I look at the environment, agriculture, soils and soil fertility. Volcanic action may be part of a natural cycle of nutrients.

In fact, this is a key aspect of the theory of “paramagnetism.” Work by Carey Reams, and covered in the book “Paramagnetism,” by Dr. Philip S. Callahan, discuss this idea. It reduces much of soil nutrition into physics, the transfer of electrical energy at the molecular level feeding growth. This is why we see glacial dust and worm castings being sold as soil amendments. Rocks feed the soil organisms that break them down so the plant roots can absorb them as nutrients, especially the many minor elements.

When Mt. Saint Helens exploded and dumped a layer of ash over central Washington, it was, at first, a huge nuisance. But, within a few years, growers in the rich, agricultural region noticed their crops were doing fine, in some cases, better, since the eruption. The mountain had brought up a rich mixture of raw nutrients, and broadcast them over a wide region. It turned out to be free fertilizer!

But I had not thought of volcanic activity being the problem it became. Not only can an extended eruption play havoc with the transportation, affect economies and public health, but it could lead drastic climate change. One European climate expert said it could lead to extended, colder winters and reduced crop production for several years. Luckily this specific event seems to be settling down, but I don’t want to think where it could send the fragile world economy if it continued.

Yet, it also seemed almost a practice run of what would take place, over several decades, if there does become an oil/natural gas shortage. I mentionedThe Long Emergency several posts ago and have continued to re-read it. James Kunstler’s chapter on banking, investing and our financial system was probably written in 2004. His predictions were dead-on for what finally happened in 2008. You tend to listen those whose predictions start ringing true, so again, this book deserves your time. Since it is older book, I am sure it is available in many libraries or used. Check with Powell’s Bookstore online at www.powells.com.

As I mentioned, the eruption actually, in the long run of a few years, had a positive effect by providing a fresh, dusting of rock that used in the complex soil microbiology as food. So, let’s not hate volcanoes.

Monsanto Products Questioned
This week two articles appeared concerning Monsanto’s products, one an herbicide, the other a transgenic crop.

First, here in Oregon, we are following a regional alfalfa grower who has forced the company all the way to the Supreme Court today (April 27). His claim is that Monsanto’s transgenic alfalfa crossed with his crop, which then limited where his alfalfa can be sold. The article in the Oregonian points out the existing rules for approving this crop for general release were not even followed.

Then, another report on recent research showed that the “Round-Up resistance” is spreading to other plants, many which are common weeds. Won’t that eventually defeat the strategy and require another new herbicide to be developed? I guess Monsanto wins either way, but weed control can be simpler and weed growth greatly reduced just by having healthy soil. Believe it or not, weeds tend to grow in poorer soils and can be indicative of specific nutritional problems. More on that in a later post.

A related research story from AgCanada.com reported that scientists at the Saskatchewan Ministry of Agriculture Crop Protection Lab confirmed herbicide carry-over in ag soils. It was at levels that damaged the following sensitive crop. This is another reason for planting fields with certain cover crops that remove the negative compounds so other following crops are not harmed. And another reason to revisit how we control weeds, again looking at healthier soils.

And then, the other night, I stumbled across a 2008 documentary on Monsanto, called “Monsanto,” on the Sundance Channel. I knew much of the history, having followed the company for years and having read many well-researched commentaries. It was clear that the company focuses on stockholder demands. This drives it to take what are interesting technologies, combine them with rigid market agreements, and twist it into a rather arrogant sales strategy. Much of genetic engineering may be fine, but let’s just take one step back and study it more.

But, actually, my main concern is Monsanto’s deliberate, and brilliant, plan to corner the “seed” market. I am not just talking about Round-Up Ready soybeans, but a much, much wider net the company has thrown over the entire seed industry. The company has bought dozens of smaller seed companies over the past decade. Once they “own” all the genetic material that creates the annual food cornucopia, they can slowly (or not so slowly) ratchet up prices and demand the growers not save seed from “their” crops. The documentary includes several instances of just how far Monsanto will go to harass growers that don’t use their seed.

Seeds are literally the transference of life. Groups like Seed Savers have formed networks so there will be a genetic base of common vegetables and other food plants readily available to gardeners. It is an effort worth supporting. It is an effort that is part of making sure we can feed ourselves.

Enough for now…see you soon.

Show Me the Research

Posted by sustainable_hort on April 4, 2010  |  No Comments

It seems that for decades the conventional agricultural community responded to organic claims with “ show me the scientific research.” That, in fact, was what led me back to Oregon State University many decades ago. I was growing food organically but did not feel I had my science in order. But, their response was valid in a sense. There was not recent research that could back it up. But, if one ventured back to before World War II, there was a body of work (see the earlier post titled Soil Health and Organic Fertilizers for a short list of key sources) that seemed to support organic agriculture strategies.

Time limits me to maybe one long article a week on this blog. But, as I do research for my writing, I come across many interesting and pertinent stories, articles, studies, and books. It is information I sense has a place on this blog. So, at least a few times a month, I will post “Show Me the Research” notes. As a visitor, this will help you identify the more in-depth pieces, from simpler informational pieces. Again, I want to thank everyone for their positive comments.
So, for the first “Show Me the Research.”

First, some more book recommendations. The first is the The Long Emergency, written by James Howard Kunstler. Though is was first published five years ago, its content and message remain topical, maybe even more so today. I first read it years ago, but recently found a used copy, bought it, and have been re-reading parts of it. It is not a diatribe against global warming, though it includes the topic as part of an overall discussion of our economy’s dangerous reliance on petroleum for much of our lifestyle, energy, food and industry. Kunstler clearly shows that petroleum is at the base of many products, and as the world economy moves to duplicate US and European models, it will become a limiting factor. His best-case scenario seems to be that everything will cost more, much more. The alternatives are less comfortable to imagine. Many other books cover some of the same ground, but none are as complete or so soundly based on solid research.

The other work is much newer. The End of Overeating by David A. Kessler, MD, jumps into the current discussion on diet with a slightly different approach. Kessler looks at how and why we eat, clearly showing how food manufacturers manipulate “sugar, fat and salt” to over stimulate our appetites. These “manipulations” work surprisingly well, leading us to both overeat and consume foods that are not as healthy. The dozens of books published on diet topics generally tell us what to eat, but don’t explain why it so difficult to control our eating. A fascinating work by the former commissioner of the US Food and Drug Administration who successfully fought the tobacco industry. Now, with this book, takes a lead role in giving us tools to change what Michael Pollen describes as “the catastrophe that is the modern American diet.” Read it and then eat.

• Herbicide Resistance Identified…The Nebraska Rural Radio Association reported that “Kansas State University (KSU) scientists have completed long-term evaluations of a limited number of independent kochia (Kochia scoparia) populations on privately-owned land in western Kansas that are now confirmed to be glyphosate (Round-Up)-resistant.”

In the western U.S. and Canada, Kochia, or “fireweed,” is often found in arid and semi-arid croplands, rangelands, pastures, and non-agricultural sites. Very adaptable, Kochia even grows on saline and alkaline soils. It a serious “weed” and control will now be more complex and expensive. This resistance developed naturally, possibly due to growers using lower rates that left a few tougher plants, not through genetic modification. But, it points to why there is concern about this happening as “Round-Up resistant” crops are planted. I am not saying that genetic modification is all bad, but this type of natural resistance seems to require science to study this closely. This type of manipulation could actually lead to faster development of resistance in the environment.

• Since I also co-own an organic produce farm, I like to see people eat more vegetables. Now more proof fresh, nutritional produce is important…worth more of your food dollar.

1) Carolyn Lister, research leader at the New Zealand Institute for Plant & Food Research told www.newkerala.com that while fruit has tended to attract the greatest attention and the ‘super food’ label, there is a body of clinical research underlining the significant health benefits of vegetables in both raw and cooked form, with broccoli along with the other brassicas, tomatoes, onions and other alliums proving to be the vegetables with the strongest scientific evidence behind them.

“This evidence varies from in vitro studies through to human feeding studies,” she claims. “Although there is considerable variation in the results of different studies…looking at the summation of results, there is quite strong evidence for benefits to human health of a number of vegetables.”

Lister is a key scientists with the Vital Vegetables program, working to develop vegetables with increased health benefits, using traditional breeding techniques.

This is similar to a new study by researchers at the University of Alabama at Birmingham has released a study indicating that anti-oxidants – plant-based substances in foods such as broccoli, berries, tomatoes, spinach, carrots, grapes and garlic, are a key in preventing the flu.

“The recent outbreak of H1N1 influenza and the rapid spread of this strain across the world highlights the need to better understand how this virus damages the lungs and to find new treatments. Additionally, our research shows that anti-oxidants may prove beneficial in the treatment of flu,” said study co-author Sadis Matalon.

2) Other work shows “flavonols” might reduce women’s stroke risk. This has been reported by Dutch researchers in the Journal of Nutrition.

“We showed for the first time, to our knowledge, that flavonol intake was inversely associated with stroke incidence,” wrote the researchers. “We conclude that evidence is accumulating that flavonol intake is inversely related to different cardiovascular disease outcomes,” they added.

Despite reporting a potential risk reducing effect of compounds from tea, onions, apples, and broccoli the results should be “interpreted with caution.” The study followed over 110,000 people, noting higher consumption of flavonols, mostly tea in the Dutch population; and from tea, onions, apples, and broccoli in US studies, accounted for the reduction in stroke risk.

Flavonols are “flavonoids,” which also include anthocyanins (berries), isoflavones (soy), flavones (parsley and thyme), flavanones (citrus), flavonols (tea) and proanthocyanidins (berries, wine and chocolate.) Boy I like those last two! An editorial in the American Journal of Clinical Nutrition (July 2008, Vol. 88, pp. 12-13), echoed that statement, saying the “contribution of flavonones to a person’s antioxidant capacity was significant.”

• Finally, good news for those of us guys who are night people and require multiple cups of coffee to survive the morning.

A recent US study indicates that coffee may boost prostate health. It said “increased intake of coffee may reduce the risk of lethal and advanced prostate cancers by 60 per cent.” The study followed almost 50,000 men for over four years and found that males with the highest intake of coffee had significantly lower risks of aggressive prostrate cancer. The study is said to be the first study of its kind to look at both overall risk of prostate cancer and risk of localized, advanced and lethal disease.

“Coffee has effects on insulin and glucose metabolism as well as sex hormone levels, all of which play a role in prostate cancer. It was plausible that there may be an association between coffee and prostate cancer,” said Kathryn Wilson, PhD, from Harvard Medical School and the Harvard School of Public Health. The researchers presented their findings at the American Association for Cancer Research Frontiers in Cancer Prevention Research Conference late last year.

Well…that’s enough for one reading. See you next week with the second “Show Me the Research.”

Plant Lists for Bioswales and Rain Gardens

Posted by sustainable_hort on March 18, 2010  |  No Comments

This post, as promised, presents a quick overview of the various plants used in bioswale and rain garden environments. It is not as simple as just throwing a few water tolerant plants in the ground. Careful plant choice and placement play key roles in successful “wet” landscapes.

Plant selection for these projects is driven by several key factors including the following:

Obviously, the basic site conditions play a huge role. Factors like sun exposure, soil depth, physical and chemical properties and moisture holding capacity can vary, so need to be understood for successful plantings.

What is the intended function of the project? For many projects, the landscape’s performance, including infiltration, pollutant removal and evapotranspiration rate will determine its success.
But, there can also be safety issues, which may require added protection such as surrounding hedges. Finally, aesthetics play a role since many working landscapes sit in neighborhoods and other public areas. While visible, they can seen as an amenity, and even provide some recreational opportunities.

No landscape is going to be maintenance free; so long term needs should be studied. This is one area where the plant material choice can have dramatically different cost impacts.
Finally, recognize each site’s natural water regime. Check the depth, frequency and duration of soil saturation, which will vary daily, seasonally or annually. For instance, Portland, Oregon, is considered a “wet” climate, but the summer is extremely dry. Plants in these urban, constructed wetland must survive extreme variations. A similar garden in Atlanta, Georgia, or Columbus, Ohio, would get significant summer rain.

Actually every rain garden or bioswale has its own “zones” that have different requirements, according to the Virginia Department of Forestry’s Rain Gardens Technical Guide. The guide points out that the center, and deepest, part of the garden best grows the very wet to wet-loving plants. Meanwhile, the middle of the garden’s side takes wet to dry plants, while the upper rim takes drier types of vegetation.

The guide lists other factors affecting the choice of the plants for rain gardens:
• Decide on objectives, such which wildlife you want to attract, then decide on the varieties you would plant to attract those species. [Refer to reference list below]
• The rain garden’s location affects use of fruit-bearing plants and trees, since if it is near the driveway or walkway, it could create messes and maintenance issues. Trees next to a power line or too close to a house are not good choices.
• If the bioswale are near enough to receive runoff from a road that gets chemical treatments for ice in winter, choose plants that tolerant salt.
And then there is actual selection of species and varieties…and a common question, should we plant natives compared to introduced, commercial varieties?

Why Native Plants?
The majority of the web sites that deal with bioswales or rain gardens are also now recommending using natives. So, why is this the accepted trend?

As Withrow-Robison and Johnson point out in the OSU publication Selecting Native Plant Materials for Restoration Projects, “selecting appropriate plant materials for restoration projects helps make any of these projects more successful. They state that, “‘appropriate’ means choosing species that are suitable for the site, are grown from locally adapted sources, and have a solid genetic composition.” In many cases, this leads to using native species.

So, what is a “native plant?” Most definitions say a “native plant” occurs naturally or has existed for many years in an area, and they can be trees, flowers, grasses or any other plants. “Local adapted sources” can mean those plants have adapted to a very limited range, living in unusual environments, under very harsh climates, or growing in unique soil conditions. Yet, while some had a very limited range, many others live in diverse areas or easily adapt to different surroundings.

So, to summarize the strengths of using natives in bioswales and rain gardens.
• First, native plants are better adapted to the local climate. Once planted and established, do tend not to need extra water or fertilizer.
• Secondly, many are deep rooted, allowing them to survive droughts. This is especially important in the Northwest, where the normal wet weather can disappear for several months during the summer months.
• Third, native plants provide habitat and food for native wildlife and, are thus very attractive to the diverse native bees, butterflies, beetles and birds, all important pollinators.

These plants, which include many wildflowers, sedges, rushes, ferns, shrubs and small trees, grow on the edges of natural wetland, also have root systems that enhance infiltration, moisture redistribution, and diverse microbial populations involved in biofiltration.

A key point to remember is that rain gardens, unlike a water garden, will be dry most of the time. Plant selection should include those that tolerate short periods of inundation, but not require constant standing water. In areas that will have moist, well-drained soil, select plants with moderate moisture requirements. For drier sites like the edge of your rain garden, plant species with low or moderate moisture requirements.
Meanwhile, any perennial plants need to be hardy in your growing zone.

Each region has growers of appropriate native and related plants for rain gardens and bioswales.

In fact, some successful growers will collect seed their own seed from the local area. For example, one Oregon native plant producer has collected seed for plants such as snowberry (Symphoricarpos albus), salmonberry (Rubus spectabilis) and twinberry (Lonicera involucrate) in the immediate area, using on a couple of mother plants for each. Another grower collects all her Pacific dogwood (Cornus nuttallii) from two trees growing at a nearby park.
See references below for several recommendation lists.

These three urban plant technologies are just part of a wider set of alternative Best Management Practices (BMPs). Many are simple, practical designs, but provide effective storm water management. Some even add aesthetic enhancements to the urban, suburban, and rural landscapes. They can be cost effective to build while providing long-term sustainability for city infrastructure and conservation of a city’s water resources. These include filter strips, grassed swale, green roof, and infiltration basin, planters and trenches.

So, as the cost savings are identified, the demand for specific plant materials should increase. At this point, the trend seems to be moving toward regionalized, native plant materials. Since there are a number of operations already propagating this niche, they may have the best opportunity to benefit from this particular green movement.

References:

The following references are available online and have been updated relatively recently, so they contain more current research and data regarding various plant choices.

• Rain Gardens Technical Guide Virginia Department of Forestry
www.dof.virginia.gov/mgt/resources/pub-Rain-Garden-Tech-Guide_2008-05.pdf

• Selecting Native Plant Materials for Restoration Projects by B. Withrow-Robinson and R. Johnson, OSU publication EM 8885-E, November 2006.
extension.oregonstate.edu/catalog/pdf/em/em8885-e.pdf

• Plants for Stormwater Design
www.wildflower2.org
Native plant database and suppliers directory for North America.

• Rain Gardens Technical Guide – Virginia Department of Forestry
Central Office
900 Natural Resources Drive, Suite 800, Charlottesville, Virginia 22903
www.dof.virginia.gov
Phone: (434) 977-6555 – Fax: (434) 296-2369
VDOF P00127; 05/2008

• Brooklyn Botanic Gardens, Rain Garden Plants.
This web site offers regionalized lists of suggested plants for rain gardens. Not as extensive as other sites, its easy to use breakdown is a good starting place in identifying plants for an effective design palette. www.bbg.org/gar2/topics/design/2004sp_raingardens.html

• 10,000 Rain Gardens (www.rainkc.com) has an extensive site that features a diverse list of plants for rain garden situations. It also has a search feature that allows criteria selection from five categories, so a nursery could focus first on what it is already growing, expand to closely related varieties, and then look for new opportunities that would fit within existing production systems.

• Bluestem Services: (www.bluestemservices.com) Has numerous plants lists, but two feature nearly 100 plants for rain gardens and wetlands.

Soil Health and Organic Fertilizers

Posted by sustainable_hort on February 12, 2010  |  No Comments

Below is another response to an online post. The basic question was “what are good organic fertilizers” and some responses questioned whether they work or not. These are my quick thoughts…the books listed below apply to sustainable horticulture in many ways.

First, I am not so sure that “plants don’t know the difference” between petroleum-based and organic nutrition. A healthy, vibrant soil community provides the nutrition, and often the protection, plants need to be in prime health. This does equal using “dry weight comparisons” as the measure of health. Plants can grow too fast, too much nitrogen actually enhances disease and pest issues, and NPK is not the only factor is consider in plant health.

There are some key works that support this idea of “healthy soils equals healthier plants,” some pre-World War II. I would suggest reading Health & the Soil and An Agricultural Testament by Sir Albert Howard, the works of Dr. William A. Albrecht, Science in Agriculture by Arden Andersen, and Ask The Plant by Charles Walters and Esper K Chandler. A more recent work, Healthy Crops, A New Agricultural Revolution, by Franci Chaboussou, examines 75 years of research in this area. It provides a fairly convincing argument against current application practices with nitrogen fertilizers and many pesticides and herbicides, since they can be shown to increase pest issues. Even recent popular works, such as Teaming with Microbes by Jeff Lowenfels and Wayne Lewis, are identifying a simpler approach to soils, what is in some ways, an older agriculture.

Secondly, I would agree there tends to be a lot of hype around these products…just look at the compost tea issue. Several decades ago, some organic products were being sold as “magic,” which over-shadowed similar products long-term benefits.

But, I went back to Oregon State University decades ago to study composting, got a horticulture degree, and ended up in the Oregon nursery industry, which grows many of its products in relatively artificial systems. I have tested the options, learned to grow most plants without excessive N, using organic pest controls (though few were even required). There is getting to be more research into soil health, we have major ag schools adding organic production to their curriculum, and the consumer is asking more questions. Meanwhile, my organic farm seems to be flourishing and early tests in a local ornamental nursery show “organic” shrubs and trees are not only possible, but may be even cost effective. These products work, you can achieve equal production, and many are sustainable…often taking consumer waste and turning it into plant food. These are natural cycles we should continue to tap.

New Environmental Technologies Demand Plants

Posted by sustainable_hort on January 24, 2010  |  No Comments

This is an article I wrote about a year ago, but most of it still applies. Those of us that have worked in the plant industry are recognizing that, as the title says…”New Environmental Technologies Demand Plants.”

With both consumers and the nursery industry, 2009’s buzzword is still “green,” with “sustainability” close behind. This is a positive for the nursery industry in several ways.
In last year’s Nursery Book, we looked at how a “green” marketing opportunity was developing, and how some in the industry were responding. This trend only continues to expand as more companies and growers change their practices to match consumer demands.
But, an equally exciting are the new environmental “technologies” that depend, to varying degrees, on plants. Commonly, bioremediation uses wetland plants to clean water and soil. Now, smaller versions, or bioswales, are finding new uses in urban areas. First green roofs, and then newer vertical plant support products are creating a “green envelope” strategy where buildings are literally covered in a plant layer.
Environmental experts are recognizing that these “natural” technologies are actually less expensive than “hard” (concrete) alternatives. They can pay for themselves in reasonable timeframes and produce long-term savings. Even large corporations that deal in huge reclamation and developments have adopted these technologies because they work, and, more important, are cost effective.
“These are no longer just warm-fuzzy things we’d like to do,” said Paul Morris a landscape architect that works on planning and sustainable issues for Cherokee Investment Services, Inc., an international development firm. “There are calculable benefit costs that can now be identified.”
Innovative landscape firms have a tremendous opportunity to join this effort, position themselves as “green,” and dramatically increase their business.