GROWING ROSES ORGANICALLY

By

Vaughn A. Hardesty
Maine Rose Society Member

 

I guess this is a good example of what happens when you open your mouth.  I mentioned to Steve that I thought it would be a good idea to start a column, in The Rose Bowl, about dealing with growing roses the natural way.  The next thing I know, Lilyan e-mails me and tells me I have two days to get an article in for the next issue.  While I am happy to contribute articles, I would encourage others to submit articles on this topic in the future.

 

I must admit that I am a newcomer to this area of rose growing.  Like most of you, I have used fungicides and pesticides to control the various insects and diseases encountered in growing roses.  Being married to Phoebe (who works for a soil and water conservation district) and loving to fish, however, has made me increasingly aware of our environment, especially our soil and water.  As a consequence, I thought it would be interesting, beneficial, and challenging to see if one could grow roses without the “benefit” of chemicals.  To this end, I have been amassing as much information as I can in regard to growing roses the natural way.  To be sure, I have just begun and I welcome input and information from others.  In future issues, I hope to cover various topics including soil, organic fertilizers, and disease resistant roses, to name a few.    The present article will focus on the use of organic methods to suppress insects and diseases. 

 

Perhaps the first question one needs to ask is, why do I grow roses?  Is it for exhibition or show?  For the most beautiful blooms?  Perfect foliage?  For my own enjoyment?  The second question might be, what are the environmental and health consequences of my spraying?  Depending upon the answers to these questions and one’s tolerance for imperfection, one can engage in suppression or control on a continuum from chemical strategies to integrated pest management (IPM) or least toxic method, to total organic gardening.

 

To grow roses organically, one must start with good soil for it is from the soil that plants get their nutrients for healthy growth and thus, their ability to suppress and fight off diseases and insects.  By good soil, I do not simply mean whether or not it is clay, sand or loam, but soil that contains the biological diversity of organisms that make up the soil food web.  Chemical sprays and fertilizers do nothing for the soil, and in some cases, may cause great harm. 

 

Next, select roses that are more disease and insect resistant.  This probably varies from area to area, but I have found that in my garden, Rugosas, Albas, Bucks and some of the Agriculture Canada roses appear to be more resistant to the slings and arrows of diseases and insects.  Thus, they require less help in fighting off these enemies.  Choosing varieties that are more “chemically dependent” only makes your task more difficult.

 

No matter how healthy our plants are, however, there will be insects and diseases.  The following are some of the interventions that have proven helpful in fighting these organically.

 

Methods and Products for Fighting Disease:

 

Compost:  While we know that compost is good for our soil, I attended an interesting workshop last year on the use of compost for the suppression of diseases.  Compost can actually help suppress disease by competition, antibiotic secretions, predation and induced systemic resistance.  Cold compost probably works better than hot and it should be used as a mulch and worked into the top inch of soil.  One can also make “compost tea” to spray on the roses.

 

Anti-transpirants:  Wilt Pruf and Cloud Cover are generally thought to work as fungus controllers by coating the leaves, thus preventing fungal spores from entering the pores in the leaves.

 

Sulfur-based fungicides:  An old weapon of choice for battling fungal diseases. 

 

Baking soda:  Combined with horticultural oil, baking soda has proven to be a relatively effective method for controlling mildew and blackspot.  Use one rounded tablespoon of baking soda mixed with one tablespoon of horticultural oil per gallon of water.  Spray weekly or after a heavy rain.

 

Whole neem oil:  This is a promising new product, sold as Rose Defense, and is available from the Green Light Company (Box 17985, San Antonio, TX 78217, (210) 494-3481).  A number of garden supply catalogues also offer this product. This is different than products made up of neem oil extracts and is said to be effective against black spot, powdery mildew and rust, as well as many insects and mites.

 

Rose Flora:  The active ingredient in Rose Flora is a soil-based bacterium that is a non-toxic based bacterium.  It is said to work by releasing millions of nitrogen fixing bacteria, which release high-energy nutrients and supply essential nitrogen for optimum growth.  It also rejuvenates and conditions the soil.  Rose Flora can be ordered by contacting Rose Flora, 603 Kimball, Excelsior Springs, MO 64024 or on the Internet at http://www.better-flora.com.  I have this product, but have not used it yet.  Hopefully, I can report on it at a later date.  Several individuals have reported positive results.

 

BioVam:  BioVam is a Mycorrhizal soil Biotic that contains Glomus Species Endomycorrhiza, which serve to enhance plant development.  The Mycorrihiza fungi become an extension of a plant root system, which increases the root coverage significantly.  It forms a powerful relationship beneficial to the soil, the plants and the fungi.  Chemical fertilizers can kill the fungi and one should not use products with phosphorus above 2%.  BioVam can be ordered from T & J Enterprises, 2328 W. Providence Ave., Spokane, Washington 99205 or on the web at http://www.thomas@tandjenterprises.com.  I have purchased this product and have treated about ¾ of my roses to date.  I am very excited about this product, as are a number of fellow rosarians.  Members of The Pensacola Florida Rose Society and the Raleigh North Carolina Rose Society of reported on this product and have reported positive results.  A number of individuals have reported that they have not had to spray at all. 

 

Compass:  This is a fungus-based fungicide that has a suppressive effect on other fungi, reducing competition for nutrients.  Haven’t tried this one, as it is very expensive, but others are saying that it may wipe out blackspot.

 

As with other products, as ounce of prevention is worth a pound of cure.  All  of the above products should be used on a regular basis before problems arise.

 

Insect Pest Sprays:

 

Water:  Keeping plants clean helps prevent problems with spider mites, aphids and other pests. 

 

Horticultural Oil:  Horticultural oil help control a wide variety of rose pests, including rose scale and whitefly.  These oils also help control soft-bodied pests, such as aphids (and their eggs) and spider mites. 

 

Insecticidal Soaps:  These specially formulated soaps are effective against a wide range of mite and insect pests, particularly soft-bodied insects such as aphids, immature scale, leafhoppers, mites, thrips, and whiteflies.  While soaps have a minimal impact on beneficial insects, I focus on spraying the buds just as they begin to show color.