Concerning 2 Neem based products (neem seed oil extract (Triact 70, ThermoTriology Corp., Columbia, MD and Neem Gold, Biocontrol Net-work, Brentwood, TN), see the "interpretative summary" of the published controlled reviewed research paper linked to below.

The full paper can be viewed by clicking on the "Repository URL" given in the "interpretative summary".

Here is a link that might be useful: link to

I can't address Miracid with BS. The need for some nitrogen is to promote growth of the entire plant and to help with photosynthesis as one of the "nutrients". Too much will cause soft, sappy, elongated growth more susceptible to diseases, insect damage and frosts. Too little and your plants may not grow or flower as desired.

The guaranteed analysis of fertilizers are Nitrogen, Phosphorus and Potassium. Though there are many uses for each nutrient, the basics are growth, flowering, fruiting. For most roses in most gardens, there is enough of the basics to have some performance. In some, there are so little of each, supplementation is needed. But, in most cases, we do tend to go overboard, using much too much.

When I've had occasion to use Neem, it's been most effective as an insecticide rather than a fungicide. As for "stronger roses" being the cure for BS, it's a bit more complicated than that.

It has been determined there are five, distinct types of BS in the US. Some roses are resistant to two types; many to only one type; and a small handful to three. Only Knock Out is resistant to all of them. Notice the word "resistant", as none are "immune". Then, there are two causes of resistance. The first, referred to as "vertical resistance", is governed by one gene. Baby Love is an excellent example of vertical resistance. When grown where the type it is resistant to, it withstands infection and collapse extremely well, until the type mutates and bypasses the gene responsible for resistance. Then, the plant contracts the disease and collapses.

The second type is called "horizontal resistance". This is where there are multiple genes responsible for resistance. These types may show some infection, but seldom completely defoliate and cease growth because of it. Now this is understood, it theoretically could be possible to develop laboratory tests to determine which type of resistance a rose possesses before propagating thousands and releasing it. Even determining which types of BS it is resistant to may be possible, but all of this is hamstrung by lack of money.

Previously, that money would have come from the ARS and the big rose breeding houses. The ARS is a shadow of its former self and the big American rose breeding houses are a thing of the past with the collapse of the rose industry.

What Bill Radler, creator of Knock Out did was to collect BS infected leaves from around the country, blend them all together in a blender then spray his seedlings with the concoction to test which ones would resist infection the best. This is what led to the Knock Out series of highly resistant roses. Not that they are 'stronger', but genetically resist more types of BS than any other. Kim

Basically, if your soil is decent, your roses (or any plant) should not need fertilizer anymore than you need vitamins if you are eating a well-balanced diet. Roses have survived for 40 million years before fertilizer was invented.

I don't spray at all and simply tolerate the BS. I've never lost a rose to BS. Given that so many roses are prone to it, including older classes and species roses, I am beginning to wonder if it serves some purpose. We see something we do not like and immediately assume it is bad. There may be a survival advantage to defoliating under certain circumstances, ie, making the rose less attractive to insects. It is interesting to me to observe which roses get it and which don't. For instance, nosiettes, which were developed her in the SE/Mid-Atlatic and produces perfect blackspot conditions, rarely get BS. Roses with R. Foetida in their genes are more prone to it. R. Foetida comes from the hot, dry Middle East and had no need to develop a resistance to BS.

Anyway, there's a lot we don't know and jumping into chemicals is not necessarily the answer.

Nitrogen is the nutrient that plants need most of and also the nutrient most likely to be deficient. Generally it needs to be added each year. By contrast, a soil test might show that your soil has enough phosphorus and potassium to last for a decade or more. Available nitrogen is transient in the soil. If not used by plants, it can be washed out of the soil in a few weeks. However, decaying organic matter releases available nitrogen gradually over time, with a half life of roughly one year. So you can supply nitrogen with a rich mulch (which is fertilizer) or with regular fertilizer.

Plants need nitrogen to construct proteins, which include chlorophyll and all the special-purpose molecules involved in growth and development. Nitrogen constitutes 2-3% pf a plant's mass by dry weight.

I am careful to see that my repeat-blooming roses have ample nitrogen. I have never noticed that it causes problems like floppiness. Some roses are just floppy ('Heaven on Earth' currently). Most of my roses are sturdy and self-supporting. This season I've fed 30-1-1 lawn fertilizer twice. My roses are standing up and blooming like crazy.

Excessive use of nitrogen can burn foliage or cause stunting, so don't exceed labeled dose of any fertilizer and don't double up fertilizers.

Incidentally, it's something of an old wives' tale that phosphorus, the second number on fertilizer labels, is "for flowers." Plants use phosphorus mainly in their command-and-control systems, DNA and RNA. It is required for all forms of plant development. Phosphorus forms only 1/2 of 1% of a plant's mass by dry weight. It does not wash out of the soil. With over-fertilizing it can build up harmfully.

Here is a link that might be useful: myth of phosphate for rose flowers

Catrose - your positing the question of wondering if BS (or any other disease, fungus, etc., that we find so distressing) serves some purpose - that is the first time I've heard that thought presented. I like the line of thought it evokes. Mother nature does put us to shame in our inability to see the "big picture" of things.

So should I try to use up some of this Miracle Grow for Roses? LOL. We cleaned out our shed and I found lots of fertilizer that I had forgotten about..and quite a bit of Miracle Grow...No one has really answered about the Miracid..wonder what would happen if I sprayed my roses down with it?

I can answer about the Miracid: it doesn't work. The notion started right here on this board in, I guess, the late 90s.. A grower in Missouri thought the blackspot subsided because he sprayed Miracid, but actually it probably just got too hot for blackspot after he sprayed. Someone did a controlled trial and it had no effect on the disease. But these things, once they are floated, never go away.

I didn't mean Miracid doesn't work as a fertilizer; it works well. I meant it doesn't work as a blackspot control.

Mich, I probably read it here!

Zyperiris, you might take your cue from Michael. Lawn Food is 30-1-1, making it an "acid" food. Michael has used it twice this year, so perhaps your roses might benefit from your use of the Miracid. You already have it and as long as it has remained fairly dry, it shouldn't deteriorate as it is salt.

My feeling about diseases is they are likely Nature's way of triggering, "instructing" the rose to alter its performance to more successfully endure approaching conditions. She "flips the switch" based upon weather conditions, available water, light quantity and quality, etc., to induce the plants to do what they need to prepare for the future.

R. Arkansana is very healthy, except when higher heat and lower available water occur together. This pattern appears prior to the beginning of colder weather when the plants need to be more hardened off, containing the appropriate starches and such to endure freezes. Even where indigenous, Arkansana experiences much rust when it is hot and there is too little water to maintain active growth. I found I can actually force Arkansana to rust in my climate by keeping it too dry. Every hybrid of it I have grown except Morden Blush responded similarly to too dry conditions.

Foetida, as has been pointed out, didn't need to evolve black spot resistance as the fungus and conditions necessary to support it don't exist where that rose is indigenous. Crossing Foetida with more evergreen roses resulted in short lived foliage on plants programmed not to shed their foliage until very late in the season, long past the productive life of the leaves, resulting in geriatric, black spot susceptible foliage.

I do believe that Nature uses plant diseases to instruct plants to do what they are required to do to exist. We, through breeding types which naturally wouldn't exist in close enough proximity to one another to breed, and "unnatural selection" have created many of the disease issues we experience. Taking our cues from Nature, selecting those types which maintain their foliage health until late in the season when they would naturally succumb to disease, then permitting them to follow what Nature tells them to do, leads to much less effort, expense and chemical use. I agree it is disappointing not to be able to grow a variety we want because it doesn't perform well in our environment, but attempting to recreate the universe to accommodate something unsuitable for where you are is an expensive, labor intensive and chemical requiring proposition. Kim

If you apply the Miracid with a hose end sprayer thingy, then you're washing the foliage which could reduce BS a bit. Perhaps that also contributed to the folklore.

A lot of rosarians spray a mix of Miracid and fungicide in the belief that Miracid acts somehow to improve the performance of the fungicide. Way back in the 90's when Miracid was a hot topic on this Forum, I remeber reading a letter in the British version of our ARS magazine from a reader who had reasonable evidence that this was true. I suspect that's how the fellow from Missouri first got the notion that Miracid, all by itself, cures blackspot.

A little more on the history of Miracid.

"MIRACID VS. BLACKSPOT ON ROSES
The daunting problem of blackspot on roses may have an effective treatment. A St. Louis rose grower, upon running out of Miracle-Gro borrowed some Miracid fertilizer for acid-loving plants. Application was made by a hose-end sprayer. The next day he was disappointed to see that many leaves fell off the plants. What he subsequently began to notice was that the blackspot lesions on the remaining leaves did not spread and that new ones did not appear. Since he was experiencing a particularly invasive infestation of blackspot on his 500 roses, he continued spraying with Miracid each week. No subsequent blackspot appeared. He communicated his findings to other rose growers, some of whom tried his technique and found similar results.

During the 1999 rose growing season several growers will be testing Miracid for the control of blackspot. Because of these results Miracid will also be tested as a fungicide on other plants. These are not scientific, but rather anecdotal findings, but it is assumed that the science will follow with similar results. People have been transmitting information like this on Internet garden discussion groups. Scientific experimentation should clarify how it works with resulting recommendations for the control of fungi on many different plants. You can find Miracid Plant Food for Acid-Loving Plants (The Scotts Company) in garden centers, hardware, and discount stores.

Because of potential phytotoxicity, it is suggested that you water plant beds prior to foliar spraying. Do not spray roses when the heat index is above 85 degrees. The following cultivars appear to be particularly sensitive to Miracid: 'Hansa', 'Topaz Jewel', 'Sunny June', 'Carefree Bunch', 'Joseph's Coat', 'The Fairy', Eglantyne',and 'Garten Direktor Otto Linne'. Petunias, gladiolas, irises, and many other flowers are not sensitive to this product. It may control mildew on lilacs and rust on hollyhocks. If you apply Miracid with a hose-end sprayer don't tilt the sprayer as it can change the spray concentration. And don't apply a regular soluble fertilizer as a foliar spray while using Miracid as the fungicidal effect will likely be eliminated. Apply the fertilizer at the base of the plant. Some growers have used less expensive products with similar results.

(from HORTIDEAS ONLINE, MAY 1999 16(5), page 13)"

Here is a link that might be useful: link for quote

More on add Miracid to your fungicide spray.

Here is a link that might be useful: link to add Miracid to your fungicide spray