Growing Roses in an Organic Environment, Part One

Part One:  What Organic-Environment Gardening Means

“First… Do No Harm”: Hippocrates, Greek Physician, 460-370 B.C.

That ancient mandate is one of the most fundamental and sacred precepts of bioethics worldwide and, essentially, is what organic-environment gardening is all about.

Why, then, do so many of us, whose lifetime-avocations are growing the most beautiful flowers and gardens in the world, continue to violate this sacred precept?  Make no mistake about it, spraying pesticides on your rose garden does great harm to the environment and potentially to you, as well.  I know this from personal experience in both my parents’ rose gardens and my own, over a span of nearly 75 years.  It is only in the last five years or so that I have realized how mistaken I was, largely from the encouragement of some of the readers of my Minnesota Rose Gardener blog who advocate organic rose gardening.  And I give them full credit for showing me the right way to garden, because you are never too old to learn and change.

But we have been consistently taught that it is right to kill everything in our gardens, except the flowers, by some real rose experts.  Here's what McFarland and Pyle said in their 1937 classic, "How to Grow Roses": 

"There is only one cure for insects which eat the flowers and leaves; that is to poison them.  It is, therefore, necessary that the poison be on the leaves before the insect starts to chew.  Since there is no way of knowing when an insect wants to dine on a rose leaf, the only way to prepare for him is to keep poison on the plant all the time…."  (Emphasis mine)

Note that the authors don't recognize that there may be good bugs and bad bugs; just kill them all. But what about all the beneficial butterflies, lace wings, lady beetles, predatory wasps and the hundreds of varieties of pollinating bees?

And lest you believe that anything has changed in the 81 years since that book was written, here is an excerpt from the only article devoted to rose care in the 2015 American Rose Annual:

"Pesticides such as insecticides, miticides and fungicides are commonly applied by rosarians to control insect and mite pests and diseases.  In fact, roses require extensive inputs from pesticides in order to maintain the aesthetic quality of both the foliage and flowers.... Examples of systemic insecticides that may be used on roses include acephate (Orthene), imidacloprid (Merit) and thiamethoxam (Flagship)...." (Emphasis mine)

In my opinion, that statement is simply wrong. Roses do not require “extensive inputs” of broad-spectrum, systemic pesticides to maintain “aesthetic quality.” Orthene, kills virtually all beneficial insects and pollinators in the garden, and the systemic neonicotinoid, imidacloprid, is directly implicated in bee colony-collapse disorder and is banned in several countries for that reason.

Here in the Twin Cities, where our horrible infestation of Japanese Beetles (JBs) arrived in mid-June 2017 and didn’t go away until early October (a new record), The Minnesota Rose Society (of which I am a member) published this advice on their website last summer: “For quick knock down use Spinosad or Carbaryl.”  Of course, Carbaryl (Sevin) will knock down today’s crop of JBs (but not tomorrow’s) and it will also take out virtually every other beneficial insect in the garden, including the all-important lady beetles, as well as predatory wasps and bees.  Spinosad (Conserve SC) is not as potentially devastating to beneficials but it is also not labelled for JBs; it is primarily used for thrips and may take out beneficial beetles, like lady bugs. The underlying fallacy in spraying any insecticide on JBs is that it must be done repeatedly, perhaps daily at times, to kill the waves of JBs that keep coming into your garden for months, from as much as five miles away.  And that kind of repeated spraying is terribly devastating to all beneficial insect life in the garden.

However, JBs can definitely be controlled organically, i.e. without harming beneficials and pollinators, but it takes some effort by the gardener, both in companion plantings, which attract JBs away from the roses, and in daily drowning of JBs that land on the roses. More on that in a later installment but, in the meantime, please see my Minnesota Rose Gardener Post: “Attacking Japanese Beetles – Organically”: http://theminnesotarosegardener.blogspot.com/2016/07/attacking-japanese-beetles-organically.html .

It’s Not No-Spray Gardening!

By my definition, growing roses in an organic environment means simply “Do No Harm” and stop believing what we’ve had drilled into us for more than 80 years: that all insects are bad and must be killed, in order to grow beautiful roses. Nothing could be further from the truth! In other words, organic-environment rose growing is not about what kind of fertilizer you use (although organic fertilizers are preferable) and it’s not a “no-spray” discipline. All of us need to spray fungicides from time to time but it’s important to use the IPM approach and spray only when needed.  And it’s important to spray the right fungicide, such as Manzate, which actually kills blackspot and anthracnose leaf-spot spores.  It’s also very smart to plant only rose cultivars that are blackspot-resistant and get rid of those that aren’t.  Over the years, I have shovel-pruned many plants that I considered “blackspot magnets” and my garden is much better for it.  I did not require a single fungicide spray last year and I sprayed only once the year before.  That is a whole lot different for the environment than my old, every 10-day, preventative spray routine. There are many, beautiful, disease-resistant roses available.  I have had good results with the Buck Roses (especially Earth-Song) and the Bailey “Easy Elegance” roses.  William Radler (of “Knock Out” fame) is also breeding roses to be both disease and insect-pest resistant and is paying special attention to rose midge.  Be sure and read his excellent article on page 94 of the “2017 American Rose Annual.”

I guarantee that once you establish yourself as an organic-environment gardener you will never look back.  But know this: organic-environment gardening requires patience.  When aphids invade your garden this spring, as surely they will if you’ve been spraying insecticides for years, your knee-jerk reaction will be to reach for the Carbaryl or the insecticidal soap. Instead, get out your hose and spray nozzle and wash the aphids off your plants several times.  In a short while, the beneficial insects (like lady beetles) you are no longer killing will find the aphids left on your plants and eat them for you.  In the meantime, Syrphid flies, which love aphids, will start returning to your garden to help the lady bugs, simply because you aren’t killing them.  Do the same thing with spider mites (wash them off) and, if they persist, order in some predatory mites, which definitely do the job (more on that later).

Pictured here is the Butchart Gardens Rose Garden in Victoria, British Columbia, Canada, which is the best example of a public, organic-environment, rose garden of which I am aware. Tracy Ferreira, IPM Coordinator of the garden describes it this way:

 “The Butchart Gardens Rose garden is approximately 16,000 sq.ft. of roses planted around a 4,000 sq.ft. lawn…. The fertilizers used are not fully organic; however, we don’t use any insecticides or miticides. We may apply fungicides depending on disease pressure and weather conditions. The diseases that typically affect our roses are downy mildew, black spot and powdery mildew.”

Note the companion plantings in the Butchart rose garden and, in particular, the border of alyssum around the rose beds, which, in addition to being attractive, is there to attract beneficial insects, particularly syrphid flies, which consume aphids, thrips, mealybugs and many small caterpillars.

The Butchart Gardens Rose Garden (Photo Courtesy of Butchart Gardens)

The picture below is one of Butchart’s perennial borders right next to their rose garden.  In addition to being beautiful, this serves as an “insectary” garden, which attracts millions of beneficial insects, such as lady beetles, lacewings, predatory wasps and bees, most of which also make their way into the rose garden because there is no insecticide pressure on them anywhere in the gardens. Fortunately, Butchart has not yet encountered Japanese Beetles (JBs) but, if they do, the perennial insectary borders will take substantial JB pressure off the rose garden, which is a significant part of organic JB control.

A Butchart Gardens’ Perennial “Insectary” Border (Photo Courtesy of Butchart Gardens)

On a smaller scale, below, is one of my rose gardens, also with companion plantings and a border of “Snow Crystal” alyssum, which literally teems with syrphid flies. Also, below, is one my several insectary gardens (complete with an Eastern Black Swallowtail enjoying Verbena Bonariensis), bordering my rose gardens in Edina, Minnesota.  This garden also attracts a large variety of bees and predatory wasps.

Once again, if you spray insecticides anywhere in your gardens these beneficial insects will not be there; many will be dead and others simply avoiding the chemicals.

One of my friendly, northern, readers of the “Minnesota Rose Gardener” blog contends that honey bees (and bees in general) aren’t attracted to roses.  This experienced rosarian and exhibitor follows the conventional practice of spraying Sevin (Carbaryl) and other insecticides on his gardens to control everything, including JBs.  I contend that the reason he and others don’t see bees on their roses is that they are killing and/or deterring them.  I see hundreds of bees on my roses, including many honeybees.  Here is a honeybee on Earth Song last summer:

The Two-Step Process for Pesticide-free Roses

These two steps should be taken simultaneously.  First, establish "insectary gardens" to attract beneficial insects, such as syrphid flies, lady beetles, minute pirate bugs, lace wings and predatory wasps that attack "bad bugs" such as spider mites, thrips and aphids. As long as you don't spray things that kill them, these predators are quite easy to attract to the garden with plantings, such as oregano, dill, bachelor buttons, verbena, yarrow, zinnias, daisies, alyssum and cosmos.

The second, but equally important step, is to introduce predatory mites in your gardens.  The several varieties of these tiny arachnids are very efficient predators for pests such as two-spotted spider mites, eriophyid mites and thrips.  Based on my several years of experience, these mites perform as well or better than insecticides and miticides.  I will go into more detail in my next installment of this article but, for example, Stratiolaelaps (Ss) should be the first mite to be introduced in rose gardens.  It is a generalist soil predator that feeds on pupating thrips and overwintering spider mites.  It is also known to feed on pupating rose midge but has not yet been proven as a control.  However, several midge trials are underway, one of which is at Butchart Gardens (see below).  The other predatory mites I recommend are Fallacis and Cucumeris for spider mites and thrips, all available at Rincon-Vitova Insectaries in southern California: http://www.rinconvitova.com/

Here are further comments about the use of predatory mites for rose midge, spider mites and thrips in the Butchart Rose Garden:

“We have rose midge but have been able to keep it below our threshold of noticeable bloom loss. In 2011 we began a program to reduce midge and thrips pressure on the roses using predatory mites. For the past five years our predatory mite releases have consisted of 150,000 soil dwelling mites (Stratiolaelaps and Gaeolaelaps), in the spring, after pruning, followed by 500,000 Cucumeris on the new foliage. We then release 300,000 Cucumeris monthly, until October. For spider mite issues we do one release of Fallacis and then use Persimilis if there are any hot spots.”

Some Important Thoughts on Rose Rosette Disease (RRD)

Rose Rosette Disease (RRD) is causing justifiable concern among rosarians.  RRD is caused by a virus transmitted by the eriophyid mite Phyllocoptes fructiphilus, which is one of several hundred varieties of almost microscopic eriophyid mites that affect trees and gardens.  For several years, I have battled an infestation of tiny eriophyid “acari” mites, which damage new growth but, thankfully, do not transmit RRD.  I have had good success in the last two years controlling these mites with Fallacis and Cucumeris predatory mites (mentioned above) and I have noted that increasing the numbers of these mites over the growing season (as described in the Butchart quote above) has resulted in improved control, such that, by the end of last summer, I was seeing very little mite damage.  This experience leads me to speculate that Cucumeris and Fallacis predatory mites, used in sufficient quantities annually in rose gardens to routinely control spider mites and thrips, might also ultimately control the eriophyid-mite carrier of RRD.  Since there is no known control for the eriophyid Phyllocoptes mite, it stands to reason that fighting it with predators that prey on other eriophyid mites just might work.  I think it’s worth a try; and it’s exactly what I would do if I encountered RRD.  I will dwell extensively on the use of predatory mites in the next installment of this article.

In the meantime, as your first step toward a pesticide-free rose garden, I highly recommend an excellent book by Jessica Walliser: "Attracting Beneficial Bugs to your Garden", which changed my way of thinking about controlling insect pests in my gardens.  It is available in many public libraries, as well as both new and used on Amazon.

Also, if you would like to delve more deeply into this subject, before my next installments of this article, please see my post: “The Pesticide-Free Rose Garden”:

http://theminnesotarosegardener.blogspot.com/2016/05/the-pesticide-free-rose-garden.html  .

Please feel free to email me at jfalkersr@gmail.com with any questions you may have.

Jack Falker

@mnrosegardener

Edina, Minnesota