|
|
Home
| About PHC | Site
Map | Order Free Product Catalogue
The
Washington Post
Rooting
for Fungus by Adrian Higgins
© 2000 The Washington Post Company
Click
Here for The Washington Post Web Site
For years, foresters have known that old pine trees build up large colonies of friendly fungus on their roots. The fungus lives on sugars supplied by the tree and, in return, effectively increases the root mass of the pine.
More roots mean better nutrition, faster growth and greater resistance to pests, disease and drought.
So why isn't this stuff bottled and used for ornamentals? Well, now it is. The result is one of the hottest developments in horticulture--products that promise teeming, forestlike root life even in the sterile soils of the urban and suburban landscape. Already widely used by professional landscapers, these products are beginning to reach consumers directly.
Advocates see these stimulants as a powerful tool in the organic, biotech garden of the 21st century for reducing the use of chemical fertilizers and toxic pesticides; promoting vigorous growth; and eliminating the transplant shock for new trees, shrubs and perennials.
"It's like taking your vitamins; it's the same concept," said Holly Cyphers, spokeswoman for Plant Health Care Inc., a Pittsburgh-based company that has become one of the major players in this new biotech industry.
Not everyone is convinced. Professional arborists are divided over the value of these biostimulants, said John Ball, associate professor of forestry at South Dakota State University. Although their scientific value has been proved, he said, their benefits could be negated by conditions in the field or misapplication.
Still, the use of these good fungi--called mycorrhizae--and other products containing another class of root-building organisms--beneficial bacteria--has been widely embraced in the past five years by the green industry. If you use a tree-care company, the chances are its technicians are injecting them in your yard.
Plant Health Care has aimed its products to date at lawn and landscape companies, groundskeepers, golf course superintendents and other professionals. But plans are in the works to market directly to consumers.
Cyphers sees a day when these fungal and bacterial products will be as widely known as Miracle-Gro is today.
Newly adopted methods of production have made them commercially available, said Mike Kernan, a Plant Health Care scientist who mans a technical-advice hot line. The organisms, which occur naturally and are not genetically engineered, are collected or raised for their spores and then mixed with other ingredients for a variety of applications.
The fungi species fall into two basic types: ectomycorrhizae, which colonize the soil around the tree's root hairs; and endomycorrhizae, which live inside the root cells.
Pines, other conifers, oaks, beeches, birches and hickory are among tree species preferring the exterior type. Most other woody plants require the interior species. (Plants in the heath family, including azaleas, rhododendrons and pieris, need a third type.)
The endo types must be applied directly to the roots for best effect, which is easy when you are installing a new shrub or tree but difficult for one that is already established. Arborists typically inject it into the root zone with a syringe.
All types work by transferring water and nutrients to their host roots, effectively increasing the size of the plant's root zone. They also shield the roots against diseases. These benefits, in turn, also cause the roots to grow thicker and longer.
In an experiment conducted by Donald H. Marx, principal scientist of Plant Health Care, a mixture of fertilizer, mycorrhizal spores and soil amendments caused a 10-fold increase in the mass of fine root hairs on red oak trees after five months.
Chet Halka Jr., a nurseryman in Englishtown, N.J., who is known for supplying big, semi-mature trees to the rich and famous, said he conducted his own experiment after landscapers told him about Mycor Tree Saver, one of Marx's products. In a grove of 16 European beech trees, Halka left four alone and then root-pruned the remaining 12 by digging a circular trench beneath each tree's branch line.
Of the 12 root-pruned specimens, four were left untreated; the second group of four received a product called Roots, which uses humic acid to promote root growth; and the last four were treated with Tree Saver. A year later, he dug the root balls of all 16 trees to examine the intervening root growth.
Halka's findings: The trees that were not root-pruned showed little additional root growth; those that had been root-pruned had visibly more feeder roots. The group treated with Roots had a thick, fibrous mat of feeder roots, but the final group, treated with Tree Saver, had shaggy mats of thick, long roots.
"It's no snake oil," he said. "I plant 15,000 to 18,000 trees a year, and I use it."
Kernan, referring to the current line for professionals, said plants should be inoculated when planted or when trees have suffered soil compaction, transplantation or root damage from construction. After that, and only for cherished trees, "I would say once every three to five years, no more often than that."
Beneficial bacteria are easier to manufacture than fungi and are cheaper, though they need more frequent applications. A number of small companies now are making their own brands.
The concoction of different bacterial species helps the root system differently from mycorrhizae by increasing the plant's uptake of nitrogen and phosphorus as well as stimulating root growth. They are also of more use to herbaceous plants, including garden vegetables, than woody ornamentals, said Zemp.
Marx, in his company's literature, says these products can go a long way toward restoring the health of the soil in environments that have either been depleted through years of chemical fertilization, whose salts kill beneficial microbes, or are new sites of lifeless hardpan.
But Ball, of South Dakota State University, said it is precisely those conditions that make it difficult for mycorrhizal fungi to take hold and flourish. Other impediments: soil chemistry that is too alkaline; and the indiscriminate use of lawn products, including fungicides, that can kill off the beneficial fungus. The need for different types of fungi for different tree species presents another pitfall.
"For fungi to do best, you need healthy soils; merely adding a product [to poor soil] is like someone saying, 'I'm going to drink and smoke, but I'm going to take my One-a-Day vitamins so I'll be fine,' " said Ball. "I look at mycorrhizae as the last thing to do, certainly not the first."
Another problem is that unless your tree-care company analyses microbe populations before and after applications, the homeowner must take the treatment on faith because, unlike fertilizers, the fungi and bacteria produce benefits that are unseen. A hit of nitrogen fertilizer might green up leaves, but the biostimulants' far greater benefit of a large, healthy root system remains out of view but it makes all the difference between a healthy and a struggling tree.
Still, the whole idea of shifting from plant care to soil care is bound to rub off on the homeowner, advancing the cause of ecologically sound landscaping, Ball said.
Added Zemp: "We are seeing the effects of long-term use and reliance on chemicals in the depletion of the soil. In the Napa Valley--the richest, most fertile growing land in the world--nowadays there are many areas you can't find any presence of beneficial organisms in the soil."
Once the message is heard, "we think the potential is phenomenal for homeowners from lawn use to ornamentals," he said.
Ball said homeowner knowledge is vital to the advance of this new twist in organic gardening, but when mycorrhizae becomes a household word, he hopes the homeowner will reach for the phone, not the bottle of microbes.
"People should understand that taking care of plants requires a lot of knowledge," he said. "You don't see people with home heart-transplant kits."
Click
Here to return to the What's New
Section
©
2000 PHC Royalty Corp.
|
