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psk8er

Please help

psk8er
10 years ago

Hi folks, Please help me with this. Don't know what it is or what to do. Thanks

Comments (95)

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Michaelg, if you want to endorse Bayer spray, I respect that, since Bayer Crop-Control plant is in your North Carolina. But it's not fair to speak for everyone else, when our soil/climate are so different. To force the same rule on everyone else would NOT be democratic.

    I only speak for myself, I don't speak for others. All I know is that my roses have zero diseases given those conditions. The rose park here sprays every 10 days in humid weather, they still have black spots on their Christian Dior Hybrid Tea. Fifteen years I sprayed with Bayer and had rampant BS, with roses half-naked.

    Why do I get so much negation for everything I do, from using free horse manure, to supporting local farmers who grow corn? It's my personal choice of NOT supporting Bayer Corp. from Germany .. check out what Bayer did during the Holocaust with Jewish extermination, plus the effect chemicals have on the environment.

    That's why I don't spray, and focus on finding out what works in my particular soil climate. I refuse to let others speak for me either.

    I had the best result when I mixed red lava rock into my clay ... all 3 neighbors came to compliment on my wildflower bed, with brilliant colors. Lava rock has iron, calcium, phosphorus, potassium, and many other minerals. Later years I dumped too much leaves on that bed, and it went downhill. There's a site on growing best orchids with red lava's nutrients . See link below for nutrients in lava rock.

    Here is a link that might be useful: What is lava made of?

    This post was edited by Strawberryhill on Wed, May 8, 13 at 18:03

  • subk3
    10 years ago
    last modified: 9 years ago

    "Michaelg, if you want to endorse Bayer spray, I respect that, since Bayer Crop-Control plant is in your North Carolina. "

    Strawberry that's a ridiculous assertion you are making--that Michaelg is "endorsing" a Bayer product because it happens to be produce in NC. This would be the same very popular product that is recommended on this forum over and over by a multitude of other posters, but suddenly Michaelg is suspect. Seriously?

    I haven't been growing roses in the area of the OP long but this is what I know: very, very few people do so successfully with our blackspot pressure without spraying. Those that successfully don't spray have generally gone to great lengths to select BS resistant roses. Something the OP has not done.

  • dublinbay z6 (KS)
    10 years ago
    last modified: 9 years ago

    I don't think Michaelg advocates gardening practices based on the location of a fungicide company in his state. Michaelg has been posting on this forum a long time and I have always found his advice to be sound and usually very similar to what I do in my Kansas garden. He advises based on garden-worthy results, not on capitalist concerns about keeping a fungicide company profitable in his state.

    And no, I am not supporting Michaelg's gardening practices because there is a fungicide company in Kansas City. If there is, I didn't know that until today--so Bayer could not have been influencing my outlook--although I do occasionally use Bayer fungicide and recommend it to others with BS problems if they are looking for an effective fungicide. I usually give instructions on how to reduce the use of it also--because I don't really like spraying at all.

    I think you underestimate how "organic" some of us are in many of our practices, even though we sometimes use Bayer fungicide.

    I will back michaelg on the claim that informed gardeners throughout our country use pine bark for mulch. If someone wants to use something else for mulch, so be it--but that doesn't change the fact that knowlegeable gardeners have good reasons for preferring pine bark mulch and a newbie might do well to try out the tried and true gardening practice that has worked so well for so many gardeners. But that is up to the newbie to decide.

    Kate

  • michaelg
    10 years ago
    last modified: 9 years ago

    If somebody wants to float theories or describe experiments, however odd, that's fine. The reason I have spoken with "so much negativity" is that SH is giving. . . let's say, eccentric advice to a newbie who is in no position to know how eccentric the advice is.

    Also I have been suspecting for some time that StrawberryHill is. . . let's say, a fictional character. From time to time these have shown up on this board with the purpose of stirring up quarrels among the regulars. The fictional character cultivates e-friendships for a while and then provokes someone into criticism or angry self-defense, causing others to rise to defend the FC, etc.

  • prairielaura
    10 years ago
    last modified: 9 years ago

    The assertion that Michael gardens in sandy soil baffles me...i live near him and my entire yard is a rockpile bound together with clay. If ONLY it were sandy. Sigh.

  • michaelg
    10 years ago
    last modified: 9 years ago

    My garden is a terrace, not on grade, and one of my beds is artificially mixed sandy loam. Others are mostly clay or mostly silt.

  • psk8er
    Original Author
    10 years ago
    last modified: 9 years ago

    My goodness I never meant for any of this to happen. Again I thank everyone that has offered advise to me and I deeply regret that my question might have caused hard feelings among members here long before I even discovered this forum.
    I am just going to slow down, take a step back, a deep breath, have a cup of tea and re-evaluate the situation. I appreciate every opinion and or suggestion. I have all of the information everyone has offered and understand what everyone is saying. If I make a wrong decision it is all on me. Let's just enjoy the season while we have it :-)

  • Brittie - La Porte, TX 9a
    10 years ago
    last modified: 9 years ago

    Psk8er, I wouldn't trouble yourself. Some threads have a tendency to take on a life of their own, and there's nothing to be done about it. No worries. :)

  • mori1
    10 years ago
    last modified: 9 years ago

    Houston is right, this isn't your fault. Sadly, this happens from time to time. You've already taken the first step by having your soil tested. Let that be your guide. Goodluck.

  • Zyperiris
    10 years ago
    last modified: 9 years ago

    Well..hmmm..I am not a scientist. But when I planted my rose garden in a raised bed 4 years ago I added lots of compost, gypsum, lime..rose growing mix..mushroom compost a few times and manure. I am in the soggy PNW and I grow lots of moss around here. But I did not want to spray..I did use a dormant spray a few winters and a few times wettable sulfur. This year I have not fertilized, or sprayed. My roses..the oldest one look great. I truly believe it is about the soil and also trying to stick with stronger roses for your area. It works. It's the soil people..that and PATIENCE.

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    The following was stated: "Let me repeat, we have no reason to believe that the type of mulch has any effect on blackspot disease."

    "In 1992, less blackspot developed on plants with oat straw or pine straw ground covers than on those with landscape mat or bare soil. In 1993, lowest disease severity was observed on plants with oat straw ground cover."

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

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    Regarding the acidity of pine straw mulch, I was able to find a very complete study:

    "Pine Straw (Pine Needle) Mulch Acidity-Separating Fact From Fiction Through Analytical Testing"

    For oat straw mulch, I could only find the vague term neutral,

    Here is a link that might be useful: link for pine straw acidity

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Thank you, Henry for the info. My point is that when it's DRY AND ALKALINE, BS can't germinate. Oat straw and pine straw dries out fast after a rain. I have pine needles in my garden, it's test neutral in pH. Pine BARK is different, it stays wet and acidic for years.

    My bare soil is tested pH 7.7 more alkaline than pine needles which is neutral after 46 days (see the below link).

    Pine needles dry out faster than bare dirt. It's the pine mulch or pine bark, that stays wet longer after a rain, I pick up a piece of 2-years old pine MULCH and tested its pH: very acidic, versus pine NEEDLES or straw, that's neutral after 1 month. Optimal condition for blackspots growth: 7 hours of wetness, and from pH 4 to neutral.

    Fungi doesn't like dry and alkaline, I took both microbiology and biochemistry in college. See excerpt below on pH of Pine needles, which is different from pine bark: "From this round of tests, it is clear that the fresh green needles leachate was initially acidic at 4.5, but following several simulations of rain and drying cycles over a few weeks time ... Over a period of 46 days, the needles were no longer acidic, with the pH being that of distilled water."

    Here is a link that might be useful: Pine Straw info.

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    "Those interested in ornamental plants were not left out of the Field Day. Kira Bowen, associate professor of plant pathology at Auburn, discussed a study of new ways to control blackspot in roses, which leaves black spots on the leaves and can defoliate plants. She noted that fungicidal sprays are the best controls for this disease. She noted that using a mulch, such as pine or oat straw, that sponges water away from the plant also will help control this disease.

    "These mulches keep rain and water from splashing up on the plant," she explained. "The disease is spread when water splashes it onto the plant, so certain mulches can help stop its spread."

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

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    The link to the complete mulch - blackspot article is given below.

    Here is a link that might be useful: Auburn link

  • ND1964
    10 years ago
    last modified: 9 years ago

    This is for Straberryhill...

    Wow! I am so impressed (and jealous) looking at these beautiful rose bush! Great Job! What kind is it?
    Thanks,
    Enjay

  • michaelg
    10 years ago
    last modified: 9 years ago

    But the bar graph in the article shows pine bark as scoring better than pine needles, not worse!

    Mulch is better than no mulch because a fresh mulch covers fallen leaves and leaf fragments that may be a source of spores. Organic mulch might be better than landscape fabric because the plastic encourages more spattering. BS spores are moved around primarily by splashing water and, I believe, the gardener's hands and gloves. The spores are relatively heavy and sticky.

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Hi ND1964: Thank you for your kind words. The 1st shot of 3 rose bushes are very disease-resistant: Francis Blaise, Liv Tyler, and Evelyn. The shot with corn-meal dusting is Radio Times (too thorny!). The last shot at Cantigny rose park is Carefree Celebration, they use zero mulch, since we have alkaline clay and wet climate.

    We have 2 weeks on non-stop rain with mushroom in the lawn. My 52+ own-root roses are 100% clean ... if you want to know why, check out the English Roses Forum where I listed experiments for international folks. See link below.

    Own-roots are healthier than grafted on Dr. Huey for my zone 5a. Roses Unlimited in SC has a sale 1st week, or 2nd week, or 3rd week of June, depending on the weather ... where it's 1/2 off, only $8 per gallon last summer. They come big & healthy with blooms.

    Here is a link that might be useful: English Roses Forum and general care of roses

    This post was edited by Strawberryhill on Sat, Jun 1, 13 at 23:10

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    The following was stated: "But the bar graph in the article shows pine bark as scoring better than pine needles, not worse!"

    H.Kuska comment. I wonder if in preparing the graph the captions were mixed as when the authors in the other paper discuss the results they single out the oat straw and pine straw: "In 1992, less blackspot developed on plants with oat straw or pine straw ground covers than on those with landscape mat or bare soil. In 1993, lowest disease severity was observed on plants with oat straw ground cover."

    In the days of manual type setters, errors of that type were known to occur and when the authors (my self included) checked the proofs we read what we know we wrote instead of what was actually before us.

    It would have been helpful if they had included the table that containe the data used in the graph (with standard deviations).

    Please note, the idea that the captions may have been switched is just a maybe.

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Hi Henry: Thank you for the info. I was puzzled why my band in pine bark from the nursery looked so sick in the picture I posted up the thread.... I also put pine mulch on top of the pot. I scraped off the mulch when I tested the pH to be very low.

    Here's an excerpt from the link below: "Low oxygen composting of pine bark (anaerobic respiration) causing very low pH. This can occur in pine bark when mold (mycelia) develops in a band 24 to 30 inches below the surface of the pile. This creates a cap that seals off oxygen. Anaerobic respiration can occur producing acetic acid (vinegar), phenolic and alkaloid compounds toxic to plants. The pH may drop as low as 2.0, which causes nutrients (fertilizer salts) to be flushed from the pine bark. These can also be toxic. Check the pH before planting. If low pH is a problem, wet and aerate the pine bark. After three weeks the pH should return to about 4.0.

    Mold in the bark which repels water. Pine bark in dry piles may develop high fungal populations recognized by clouds of spores when disturbed. Once spread out and irrigated, a mold (mycelia) grows rapidly which repels water. Newly set plants may dry out and die. "

    Last year I put pine bark in a hole to break up my rock-hard clay. Yesterday I dug that hole and found white mold. I was puzzled why that hole is so dry. Never mind that we have 2 weeks of constant rain. Pine bark is the slowest among mulch to decompose, but it can destroy roots with its acidity when too much is piled up.

    From another University of Georgia document: pine bark has a pH around 4, with approximately 13% water retention when fresh, and 21% water retention when decomposed.

    Here is a link that might be useful: University of Georgia on pine bark

    This post was edited by Strawberryhill on Sat, Jun 1, 13 at 23:55

  • harborrose_pnw
    10 years ago
    last modified: 9 years ago

    I found a more complete article describing the mulch experiment work of Dr. Kira Bowen at Auburn which was mentioned above by Dr. Kuska.

    The experiments were done in the early 1990's over a three year period comparing blackspot on several roses that were sprayed with the fungicide chlorothalonil in beds that were mulched w/ pine bark, pine straw, oat straw, landscape fabric and unmulched.

    There was very little difference in disease levels among the roses planted in the various organic mulches, but disease increased where the beds were unmulched or had landscape fabric. The chart in the article indicates that roses planted w/ pine bark mulch suppressed disease a little more than roses planted w/pine straw, but a little less than oat straw. The differences appear negligible among the three organic mulches. The article appears in a pdf document of a document called "Highlights of Agricultural Research" Vol. 42, No. 2, Summer, 1995. Disease certainly did not increase using pine bark mulch. Disease w/pine bark mulch was less than pine straw. The differences appeared negligible to me, however.

    I gardened in north Alabama in the Huntsville area for about five years growing 100 roses in acidic red clay. I mulched with pine straw, pine bark, leaves and even grass clippings. I did not spray fungicides. Among all of the roses that I grew, the most disease resistant were the tea and china roses. Many of them are on Jean Harrison's list that subk listed above.

    Interestingly in the 1913 article Dr. Kuska links in another thread on "blackspot of historical interest" the r. indica roses, or teas and chinas, are noted to be disease resistant to blackspot as well.

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    I now grow about 100 or so roses in a very mild, wet climate in the Pacific Northwest. I mulch with leaves, wood chips, grass clippings or whatever else I can find, including manures of various animals. Much of my garden is covered with wet leaves from autumn through early summer. My soil is also very acidic.

    Again, what I find is that the roses that are naturally disease resistant in this climate do not get blackspot regardless of mulch type. The 1913 article makes note of the same thing as I have found. Gallicas, rugosas, albas are disease resistant. Some moderns are. Portlands are. The mulch makes no difference as far as I can see; it decays and improves the soil, and soil quality seems to make a big difference in the health, vigor and disease resistance of a plant, assuming the rose is disease resistant in the climate anyway.

    I chipped wood and used it as a mulch in a rose bed last fall. Subsequently many mushrooms appeared in a very wet, cool period. The mushrooms died over the winter, the chips have decayed and that bed has some of the richest soil in my garden. I have some very healthy roses in that bed where the wood chips have decayed and the mushrooms died. I am assuming the mushrooms will return next winter as their fruiting bodies go pretty deep. This does not scare me. They are an indication of healthy soil.

  • buford
    10 years ago
    last modified: 9 years ago

    What Strawberry Hill does may work in her zone, however, you live in Alabama and have red clay. You need mulch. If you can get composted horse manure, that is great, but that is an amendment, not mulch. In your yard, it will bake in the hot sun and turn to concrete, just as your clay soil will.

    Pine bark mulch is fine. I don't like pine straw for rose beds because I am always walking on it and it tracks into the house. I do use it on hilly areas and it's fine.

    I used to use the generic pine bark nuggets, but I recently tried using the new engineered mulch that is supposed to help with directing water to the ground/roots of plants rather than absorbing it and preventing it from getting to the ground. I have noticed a difference.

    Teas and noisettes are your friends, look into them and get these roses. They do best in our area and are resistant to BS. They will get spotty and lose some leaves, but they will not be as bad as some hybrid teas that honestly cannot survive without spraying in the hot/humid SE without spraying.

    There is a rose person, The Redneck Rosarian, who lives in Alabama and is on Rose Chat. You should check out his blog. He will probably have a lot of info that would be helpful to you:

    Redneck Rosarian

  • buford
    10 years ago
    last modified: 9 years ago

    BTW, the link above from the University of Georgia is about growing blueberries in pine bark, not using it as a mulch for roses. The southern highbush bluberry industry in south Georgia and northern Florida uses prodigious amounts of pinebark as soil. This is because the native soil is many times not suitable for blueberries. They do best in acidic soils of 4-5 ph.

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Thank you Buford and Gean for the info. Everyone soil and climate is different so I never speak for others, I only speak for myself, and from actual experience.

    In my last garden of ACIDIC HEAVY CLAY, mulching with pine bark hurt my roses' roots. They were tiny when I dug them up. Kim Rupert discussed about bigger roots mean better disease-resistant in his breeding program.

    Here's a discussion in Fig forum on how acidic pine fines hurt young roots: "Today, my pond water is at 8.33 pH and the standing water in a plastic pail of pine bark chips is 3.45 pH. I was not surprised, just deflated. I should have known that the pine bark would work to lower the soil pH. I dumped a planted nursery pot the other day and ran and showed my wife how it seemed there were pine bark fines clumped around the dead and rotted roots".

    Now in my present house of HEAVY alkaline clay, I mulch with horse manure on a bed of sawdust and recycled wood chips bedding. Nice and fluffy on top, zero gunking nor made into concrete in our hot summer 90 to 100 degrees. Recently I moved Golden Cel. ... its root is huge, and the top 12" where I piled manure/woodchips is nice and fluffy.

    Below is the base of Golden Celebration, picture taken last October, before frost. It's always clean here, not a trace of black spots. The horse manure on woodchips bedding has a pH of 7.5, slightly less alkaline than my soil of 7.7.

    Here is a link that might be useful: Pine bark discussionn in Fig Forum

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Here's the base of Evelyn, taken in this year's wet weather. It's also mulched with horse manure on wood chips, nice and fluffy and DOES NOT become concrete on top.

    Evelyn has zero diseases going into winter, and 100% clean now. Paul Neyron and Comte de Chambord are also clean, but I didn't put horse manure on those 2, just bare dirt. My soil pH is 7.7, black spots can't germinate in that alkaline range.

    This post was edited by Strawberryhill on Sun, Jun 2, 13 at 10:01

  • buford
    10 years ago
    last modified: 9 years ago

    From that same thread:

    The pH of pine bark fines generally ranges from 4.7 as a low, to 5.1 as a high, so your finding a pH of 3.45 is confounding, especially since pH is measured on a logarithmically inverse scale. I.e., a pH of 3.45 is 10 times more acidic than a pH of 4.45 and 65 times more acidic than pine bark that falls within the normal range at 5.0.

    Figs will grow just fine in an acidic media, if the nutrient solution pH is reasonable. The pH of a container substrate is much less important than the pH of mineral soils.

    Again, that thread is about growing fruits in containers of pine bark as substrate, not as mulch. It's a completely different situation.

    There is clay and there is clay. The SE has red clay which is acidic. However, most people here, and most rose growers, use pine bark mulch. The Consulting Rosarians in my local rose group recommend pine bark. I doubt as a mulch it adds too much acid to the soil. It's possible that the clay you had was very acidic, or you did not amend enough with organic material. Clay can be hard to grow in if not kept friable and moist. Adding amendments to cut up the clay and keep it porous is very important. If not, the roots will have a hard time getting through the thick soil and will grow very close to the surface, perhaps even in the mulch and that may have caused them to be stunted.

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    The pile of horse manure here is taller than a 1-story house. It becomes an environmental issue when that goes to landfill, rather than folks' garden... I learned that from Kim Rupert. I post pics. to show that horse manure works just fine, and doesn't become concrete on top.

    Roses still bloom well at alkaline range. Cantigny rose park with 1,200 roses is 15 minutes from me, alkaline clay. Chicago Botanical garden with 5,000 rose listed their pH of 7.4 with composted leaves. My garden is highest at pH 7.7, leaves are pale but very healthy, and roses bloom well.

    Below is Christopher Marlowe, planted with a big pile of horse manure at the bottom, after I removed all lime stones. I also mulched 4" thick with horse manure. He gets only 4 hours of morning sun:

  • dublinbay z6 (KS)
    10 years ago
    last modified: 9 years ago

    I have no doubt that roses with manure as a soil amendment in the soil and/or as a mulch on top can grow fine. I don't think anyone disputes that possibility. So why are you arguing? And about what?

    Kate

  • buford
    10 years ago
    last modified: 9 years ago

    Most people don't have access to horse manure. Alfalfa is the next best thing. It's actually pre-digested horse manure :) But I would not use it as a mulch.

    I don't mulch directly under my roses, I leave that bare, but it's been amended so much and is it constant shade from the roses, so it doesn't need mulch. But beyond the drip line, every thing is mulched in pine bark (or was until that storm that swept all my mulch away....). Alfalfa will not cause black spot. And if alfalfa is acidic, then so is horse manure.

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    My main criteria for a healthy rose soil is when I find that the rose roots have formed Mycorrhiza fungi associations.

    Here is a link that might be useful: link for wikipedia discussion of mycorriza

  • michaelg
    10 years ago
    last modified: 9 years ago

    I think harborrose makes the key point about the Kira Bowen article: differences among the organic mulches appear to be negligible for any practical purpose. Are they even statistically significant differences? And the findings contradict the claim by SH that pine bark mulch contributes greatly to blackspot problems or that getting rid of bark can turn defoliating roses into blackspot-free, no-spray roses. So I return to my assertion that we have no reason to believe that the type of mulch has any effect on blackspot. (I do not think of landscape fabric as a normal mulch.)

    If, as Henry speculates, the captions for bark and needles were reversed, there would still be no substantial difference.

    An important point that got lost in this discussion is that most transmission of blackspot is from leaf to leaf, not ground to leaf. Also blackspot overwinters in spots on green canes which provide reinfection to the spring leaves if there are no overwintering leaves. Infected fallen leaves are likely to play a major role only when the rose has been pruned nearly to the ground.

    Back when we had subzero winters here, I pruned hybrid teas to a height of zero to eight inches. Then I rarely saw any BS spots before the end of the first flush. With hardy shrubs and high-pruned HTs, BS started much earlier. Unsprayed roses can be defoliating by the end of the first flush. This is because the overwintering canes have BS lesions (often visible as purple spots) that deliver spores conveniently to the new growth.

    The importance of cane infections in transmitting BS explains why, in the Bowen study, there was only a modest difference between mulched and unmulched roses.

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Stuff are acidic at first, but when it's decomposed, it goes to neutral range. The horse manure I get is decomposed. The stable in my zone 5a put lime to deodorized, that raise the pH to 7.5 and above. Pine bark is slowest to decompose, thus stay acidic much longer.

    I'm doing an experiment where I mulched 2 out of 16 pots, with pine bark. The 2 pots mulched with pine bark have the slowest growth. When the root is injured by pine bark accumulated near it, it's less disease-resistant.

    A second person reported the same: •Posted by lathyrus_odoratus (My Page) on Thu, Mar 25, 10 at 3:44

    "I'm resurrecting this thread because I've recently had an almost identical experience....expect I've killed at least two plants and caused damage to at least 10-15 more. They are not fig trees, but what happened is so similar that I felt compelled to write about it here. Here's what I know:
    -Pine bark fines test at about 3.7 or so (same as the person who started this thread) ...." See link below:

    If you google "horse manure pH", folks in the Soil Forum report a much higher value than mine, at pH 8. All I know is my 52+ own-root roses are 100% clean with either horse manure at pH 7.5, or my bare dirt at pH 7.7. I don't spray whatsoever.

    Below is Pat Austin, taken today after 2 weeks of non-stop rain. She's always clean even in late fall.

    Here is a link that might be useful: PIne bark discusison in fig forum

  • seil zone 6b MI
    10 years ago
    last modified: 9 years ago

    You can mulch with anything you want but unless your roses are healthy and have a strong immune system on their own they'll still get black spot. Mulch in no way kills it or deters it from showing up when conditions are right for it. It's out there on the wind and whether you've mulched or not it will show up and grow. The key is healthy roses with high resistance not top dressings.

  • floridarosez9 Morgan
    10 years ago
    last modified: 9 years ago

    Yes, Seil, I'm proof of that. I use horse manure in the planting hole and I mulch heavily with it. Most of our rain arrives during our hot, hot summer months, and I have little trouble with blackspot. If, however, we have several days of damp overcast weather during our cooler months, my roses will blackspot, despite the horse manure.

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    I had posted the link to the Bowen full paper on Sat, Jun 1, 13 at 15:50 and then commented on Sat, Jun 1, 13 at 20:19 :
    "It would have been helpful if they had included the table that contained the data used in the graph (with standard deviations)."

    H, Kuska comment: However, Dr. Bowen apparently felt that the differences in results were significant as she singled out the oat straw results. "In 1993, lowest disease severity was observed on plants with oat straw ground cover."

    I would expect that there are times when being able to observe the actual fields allows one to see correlations that appear less significant when transcribed to a small three dimensional bar graph. I specifically mention three dimensional as I feel that that feature makes it difficult to enlarge the graph and then read the actual values from the axis. Can anyone else (possibly with a fancy program) do it?
    ---------------------------------------------------
    The following was stated: "An important point that got lost in this discussion is that most transmission of blackspot is from leaf to leaf, not ground to leaf."
    H.Kuska comment. I am interested in reading what study this is based on. The 2003 scientific paper in the link below reports: "The causal organism, Diplocarpon rosae, is spread primarily by water splash and reproduces almost exclusively by asexual acervuli and conidia."
    "In 1993, lowest disease severity was observed on plants with oat straw ground cover."

    Here is a link that might be useful: link for splash statement

    This post was edited by henry_kuska on Sun, Jun 2, 13 at 14:26

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    I agree with Seil and Floridarose!! You said it best. The key is strong root system, and good soil.

    My clay soil is high in limestone, which releases gypsum (calcium sulfate) when rain water (pH 5.6) hits. I don't have any fungal diseases on my peach, pear nor cherry trees. My fruit trees are clean, no need to spray.

    Calcium and potassium strengthen plant tissues, so I don't have peach-leaf curl disease. I don't have botrytis nor balling in my roses either. My neighbor grows 100% clean hybrid teas, no mulch, just bare dirt. I'll get my soil tested again, since the last time I scooped the top soil, with mostly dead grass and horse manure .... it's not accurate.

    I notice that the disease-resistant roses: Kordes Flower Carpet, Eye-for-you, and Kim's Lynnie all have thick leaves. In my pots experiment, I notice that the leaves became thicker when I put gypsum (calcium sulfate) in the pot.

    I have 3 disease-prone roses: Paul Neyron, Comte de Chambord, and Gruss an Teplitz. They are clean in holes mix similar to what I planted Paul Neyron last summer with Ball's potting soil: composted pine fines, lime, peat moss, perlite, vermiculite, and gypsum.

    Most of my roses are green to the tip through the winter, so zone 5a isn't a factor in keeping roses clean.

    Below is Paul Neyron well-behaved in the ground this year, picture taken today, he's NOT mulched with horse manure, so he's pale. Horse manure has iron and all trace elements to green up my roses.

  • dublinbay z6 (KS)
    10 years ago
    last modified: 9 years ago

    Strawberry, I don't understand your pictures. Either you severely prune your roses nearly to the ground (which would be a major reason why you don't see much BS infection), or your pics are all of new little undeveloped roses --which means the BS problems are probably still in the future as they grow to their normal heights.

    Take for example your picture of the hybrid perpetual--it looks about 6 inches tall. In my garden, a hybrid perpetual grows about 5 or 6 feet tall, not 6 inches tall.

    I really don't understand what you are showing in the pictures since all of your pictured roses look undeveloped or severely pruned--not normal growth, in other words.

    I'm also concerned that you are not always using terms the same way other posters are. Just a couple posts ago, you seemed to think manure as a soil amendment was the same thing as a mulch--your posters are talking about two different things when they use those terms, but you evidently are not. That makes me wonder about your repeated assertions about pine bark mulch--it's beginning to sound like you are using pine bark as a soil amendment--mixing it into the soil in the planting hole, for instance. That is NOT how your posters think of a mulch--which to them means the pine bark is spread ON TOP of the planting, not mixed into the soil in which the rose is planted. If you are indeed using a mulch as a soil amendment, I can see why you got some results that surprised many of the rest of us--because when we use a mulch as a mulch (and NOT a soil amendment) we don't usually get the results you claim to get.

    Unless we all agree on the terms we are using, there is no possibility that we can begin to understand what each other is saying.

    Kate

  • Zyperiris
    10 years ago
    last modified: 9 years ago

    UGH too much science for me! Okay..as I posted somewhere else on this site..I made a new raised rose bed about 4-5 years ago. I added compost..different kinds..and Gypsum. Also used a good soil for Roses..made especially for roses..My garden is almost BS free this year! One more new thing we did was lay down a layer of wood chips last fall..maybe that's what's helped so much. NO SPRAY so far..and I would not use one now. I don't mind the dormant sprays as there are not so many bees around. I know at first I was trying to use safe things like Neem oil for my roses..and even that went away. My weak roses like Double Delight in a pot look like hell and Octavia Hill own root is in the shade and is lush and green this year. I think for a newbie it's just important to think about putting compost and nutrients into the soil. Good soil equals good plants..and enough with the science..I do not do anything to kill the bugs..EVER..I do pick off rose slugs..lol. I think if we are patient and the soil is good our plants will come around...

    Also..Straw-years ago I lived in California and we had what we called HARD PAN soil. It was hard as a rock. We had planted 3 trees..Mimosa's...they would not grow..just sat there..and my ex got Gypsum and started throwing it around the base of those trees..it worked and eventually that Gypsum broke down the hard pan and those trees grew.

    I wish I could be so confident with my companion plants to my roses..my Clematis are struggling...thin little twigs. :(

  • strawchicago z5
    10 years ago
    last modified: 9 years ago

    Hi Zyperiris: I'm glad to hear from you. Thank you for the info. that gypsum breaking down hard clay.

    Paul Neyron was a tiny band last fall, the winter-kill was severe on that one. I was talking about MULCHING with acidic pine bark in my last house of acidic clay, with roses that black-spotted badly .... their roots were hurt by the pine bark's acidity.

    I was talking about the experiment I did MULCHING with 2 pots out of 16 with pine bark ... slowest growth so far. I'll report the experiment elsewhere so I won't be nit-picked.

    I do have big hybrid teas that were green to the tip. I only pruned 1/3 off in spring. Here are hybrid teas Sweet Promise, and Firefighter next to it. Feel free to put down my pictures ... I won't be around to see your comments:

  • michaelg
    10 years ago
    last modified: 9 years ago

    I said: "An important point that got lost in this discussion is that most transmission of blackspot is from leaf to leaf, not ground to leaf."
    Henry quoted that and answered: "I am interested in reading what study this is based on. The 2003 scientific paper in the link below reports: 'The causal organism, Diplocarpon rosae, is spread primarily by water splash. . . .'"

    --Henry, surely you understand that "water splash" can carry blackspot spores from cane to leaf and leaf to leaf? Surely you are not asking for a study to verify that?

    Horst in the Compendium, immediately after describing conidial sporolation in LIVING leaves, says, "Conidia are disseminated by splashing water. . . hands. . .insects." "The fungus overwinters as mycelia in fallen leaves or on infected canes." "The fungus does not survive in the soil" (1st ed., 10).

    The fungus is not in the soil. If fallen leaves are covered with a new layer of mulch, infection of new growth in spring is going to come primarily from infected canes and old leaves hanging on the plants--carried to the new growth by splashing water. But if roses are pruned to the ground, infection will be delayed until spores from fallen leaves make their way up through the mulch and are splashed up onto new growth. Once new growth is infected, it seems obvious that the season's infected leaves (living or newly fallen on top of the mulch) become a more important source of spores than last year's fallen leaves buried under mulch.

    I am skeptical of claims about the effect of soil pH or the particular type of mulch because BLACKSPOT IS NOT A SOIL FUNGUS. Blackspot colonizes the above-ground parts of a susceptible plant and lives there pretty much permanently.

  • Zyperiris
    10 years ago
    last modified: 9 years ago

    Somebody's angry and not coming back? Well whatever..lol

  • Kippy
    10 years ago
    last modified: 9 years ago

    Michael

    Are you saying that if you live in an area that has winters that regularly cause die back so far that you have little cane left vs an area with a warmer winter with canes that stay viable, you would have less blackspot even with the same disease level for the area?

    Not really a worry for me here, but curious how much temperatures would vary the level of disease when all else is the same.

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    Michael in your original statement you stated "most" ( most transmission of blackspot is from leaf to leaf, not ground to leaf."

    I was interested in your reference for "most". I am sorry if I did not make it clear.

    I have no problem with your quote from Horst: ""The fungus overwinters as mycelia in fallen leaves or on infected canes." It does not include a "most".

    Now you are limiting your statement with a "If fallen leaves are covered with a new layer of mulch, infection of new growth in spring is going to come primarily from infected canes and old leaves hanging on the plants--carried to the new growth by splashing water."

    That is a completely different statement than your original one. I have no problem with that one. If you remove the possibility of one; than, yes, most has to come from the other.

    -----------------------------------------------------

    Regarding the effects of different mulches and pH.

    In another thread I introduced that a scientific study has shown that horse manure fosters the friendly anti backspot Trichoderma fungi. It is also possible that the soil pH affects the blackspot due to its effect on friendlies.

    A cornmeal mulch has been reported to decrease blackspot (see threads in organic roses forum) and it also is known to foster friendlies.
    -----------------------------------------
    Some tree mulches should also help: "A total of 37 species were found on decaying litter of all 3 tree species. These included .........Trichoderma album Preuss, and T. viride Pers. ex Fr."

    From:

    Title: "FUNGI ISOLATED FROM DECOMPOSING CONIFER LITTER"

    Author: JOHN W. BRANDSBERG

    Published in: Mycologia, Vol. 61, No. 2 (Mar. - Apr., 1969), pp. 373-381.

    Here is a link that might be useful: link for decomposing conifer litter

  • michaelg
    10 years ago
    last modified: 9 years ago

    Kippy--Yes, I have direct experience with this effect, owing to a change in our winters from zone 6 and sometimes 5 in 1976-85 to consistently zone 7 for the past 25 years. (Most hybrid teas are cane-hardy down to around +5 degrees, or middle zone 7, unless they have suffered defoliation.) When I had to prune severely each year, I was able to manage blackspot on hybrid teas with an organic fungicide (sulfur), and the first spots did not appear until late May or early June. Downside was that the plants were small during the first flush. Nowadays I have 6' plants by this time of year and lots more flowers in the first flush, but I need a more effective fungicide than sulfur if I want to grow a few HTs well.

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    I wonder if an early spring spraying of the canes with Wilt-Pruf would be useful.

  • michaelg
    10 years ago
    last modified: 9 years ago

    Henry, good idea. I've thought about trying that but never have done so. It would be so hard to tell whether it did any good or not, because I have hardly any duplicate varieties. I wrote to Kira Bowen once with some ideas for trials, I think including this one, but she didn't respond. The idea would be to seal the cane lesions at around pruning time so they release fewer spores to infect the new growth. The film of dormant strength WP is supposed to be good for about 6 weeks. However, the blackspot acervulus generates enough pressure to break through the cuticle, so I don't know that WP would contain it. It has been reported that oil sprays have a partial smothering effect on sporulating acervuli.

  • harborrose_pnw
    10 years ago
    last modified: 9 years ago

    Just another comment on the mulch discussion.

    If oat straw mulch were superior, I am guessing that it would be the mulch currently recommended by ACES, but it isn't even on the list of mulches currently recommended on a 2012 gardener bulletin.

    I went through master gardener training (no great commendation, I understand) under ACES and have never heard oat straw recommended, but pine mulch isusually first on the list . I've read a paper showing that pine straw carries a lot of weed seed, also.

    But I do not think that oats are grown in Alabama to any great extent so oat straw as a recommendation to Alabama gardeners would be out of character, I think. Pine trees are common in many sections of Alabama, though.

    Does blackspot germinate anywhere except on rose tissue? I think I've read that attempts to germinate it in agar, for example, didn't work.

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    harborrose, See: link below

    Here is a link that might be useful: germination on agar

  • harborrose_pnw
    10 years ago
    last modified: 9 years ago

    That's interesting, Dr. Kuska, thank you. Does it germinate w/o an agar source on mulches of different kinds?

  • henry_kuska
    10 years ago
    last modified: 9 years ago

    Regarding growth w/o an agar source. Apparently the paper always used at least some agar. It is based on a Ph.D. Thesis. Perhaps there would be some information in the Historical Section that would answer your question. This is what the paper states: "The basal-synthetic culture medium was the glucose-asparagine medium of Lilly and Barnett (1951) adjusted to pH 6.0.medium."........... (H.Kuska comment: In one kind of experiment) Cellulose and starch were incorporated into the basal-synthetic medium which was solidified with 2 per cent agar. High-grade filter paper cut to a pulp in a Waring Blendor was used as a cellulose source, and soluble starch was employed at approximately 10 g./l".......... "Growth on cellulose and starch, though not dense, is quite good after six weeks."

    -------------------------------------------------------------

    There appears to be a pH effect on germination. The following is a quote from the full paper: "The greatest mycelial growth occurred at the lowest pH value at the end of the third week. As the pH started to rise more growth would be expected to take place, but on the contrary, the mycelial dry weights were less at the end of the fifth and sixth weeks."
    -------------------------------------------