1. Rose slugs/Sawfly. He listed this as a common pest rose-growers deal with and this pest is pretty bad in my garden. I was shocked to read his comment that it isn't normally a problem except in gardens that are not maintained properly/are ill-kept. What does that mean? I clean up rose debris and cut stuff back in the fall so the frost can do its work, is there something else I should be doing so that my garden is not ill-kept? Or was his comment more pertinent to his colder climate?

2. Alfalfa. He listed this as a possible food for roses but mentioned that it left deposits of something in the soil. Help me -- what was it that alfalfa left behind and is it something to be concerned about?

3. Hardwood mulch, nitrogen, and corn meal. He discussed options for mulching roses and pointed out that hardwood mulch was effective but took nitrogen from the soil and recommended using corn meal to counteract the nitrogen leaching. I had never used corn meal before but took his advice and sprinkled it on a big new bed before I laid the hardwood mulch in late July. (In the winter I had mulched with three to four inches of horse manure but it was not enough to suppress the weeds.) In this bed I had planted a couple hundred foxglove seedlings and some gallicas and damasks. Everything had been growing like wildfire and the roses to my amazement were not only getting pretty huge for new bands but were also staying clean. Three weeks after the cornmeal and mulch, my foxgloves started shrinking and two-thirds of them died. The roses began to rust horribly. I know the problem could be many factors, but could it have been the fault of the corn meal, which I also understand can be used as a pre-emergent and maybe had some negative effect? Some things you read make it sound like a cure-all but I haven't heard of it causing damage. Can anyone tell what I did wrong?

Fortunately, the foxgloves that survived are beginning to rebound a little and the roses are still putting out new growth and that is clean and staying clean so far.

I hope this isn't too much for one thread and I appreciate any responses.

On the sawfly/poorly kept garden correlation I too would love to hear others thoughts. I live in a high blackspot area and my blackspot issues don't even compare to the devastation I have from sawfly larva. If there is a garden practice I can change to mitigated it please share!

I am at a loss to explain why "poorly maintained" gardens would experience saw fly issues more severely than "properly maintained" gardens, unless Peter is considering not spraying to control the saw fly "poor maintenance". Kim

"Rose slugs overwinter in debris, and they should never be a major problem in a well-kept garden."

And I was able find the part about alfalfa:

"Like anything organics can be overdone, and some rosarians who have gone overboard with alfalfa have developed near-toxic levels of boron in their soil. This has usually happened only following many years of applications..."

Comments? What might overboard mean? What if you used alfalfa three or four times a year in the form of a strong tea as well as putting it in the planting hole? Is that overboard?

Whole cornmeal is not something you would use to add nitrogen. It has only around 1.5-2% nitrogen. However, corn GLUTEN meal is very high--9% nitrogen. If you "sprinkled" regular cornmeal I doubt it would have substantial effects on plant growth. However, if you applied 2 oz of corn gluten meal per rose, that would be a substantial fertilizing.

I don't see how the wood chip mulch could cause temporary crop failure, unless it caused fresh manure and (?) corn gluten meal to suddenly heat up and release too much N, but you say the manure had been there for months..

Rose slugs--maybe he means that if you don't control them, they mature, reproduce, and get worse. Or maybe the bad practice would be wiping out predatory insects such as wasps. These control rose slugs in many gardens. But just being a messy gardener couldn't have anything to do with it.

Alfalfa--maybe he is thinking of rabbit food, which has salt added. Otherwise alfalfa is just plant material.

(I think I also remember someone commenting on one of the rose forums that boxelder trees hosted this pest. We have boxelders on our property.)

Michael, thank you so much. You always explain things in a way that I can understand. I get very confused by some of the soil and amendment threads and I am always very worried about making a mistake. My manure was well aged when I put it down in February/March: dark, rich and full of worms :) That's right about the corn meal/gluten meal, I forgot about them being different. When I read about the corn gluten meal, I wondered if corn meal could be substituted and if I am remembering correctly I read on one of the organic forums that it wasn't as strong as the gluten but that it did have some nitrogen. I didn't want to go out and buy something and I was hesitant to fiddle too much with my soil because I don't know what I'm doing. So I thought, okay, the corn meal should do a little good and that's enough for me, as I've mulched for a long time and never noticed that it was a problem. Anyway, that's more specifically what I did. From what you say, it shouldn't have produced such negative results. I just don't know what could have happened. It didn't happen in my other new beds where I mulched and "forgot" to sprinkle on a bit of corn meal. The foxgloves there are looking good and there is none of that rust (which I've never had before).

Sorry to go on so in such a long boring manner. How tiresome of me!

No, Spinosad is an organic bacterial (as long as the brand purchased was produced through an "organic" method) which needs to be sprayed every two weeks to control the listed insects. Yes, it can be toxic to bees, but there are very few "insecticides" which aren't. It isn't systemic nor should it be applied to the soil. My personal preference, and it is my "preference", not a condemnation of the products nor anyone who finds them easier and more effective to use, is not to use anything systemic. I don't know how long they remain in the soil, nor how much potential risk I run of absorbing them through my hands when working in that treated soil. So, I just don't use them whenever possible. The rare occasion I do, I make sure never to have to handle the soil in which they have been poured.

Mention was made about roses under trees being more susceptible to saw fly, possibly due to their being "stressed." I guess that could be a factor, but my impression has been it was as much due to the conditions under trees being more conducive to their proliferation. Like aphids, they prefer more "green house conditions", cooler, milder, more humid than many sunny situations. Shaded areas are frequently more like that than exposed, sunny spots are, particularly here where the general conditions do not favor their existence. As I said, here in my garden, I only find them in very sheltered spots and only in very mild, "green house-like" weather. Kim

We do have a healthy number of wasps but have not achieved any sort of balance as far as rose slugs are concerned. And I'm worried that they're going to get worse each year. I tried insecticidal soap this spring and the squishing. Michael was very helpful then too. But it felt like a losing battle. For example, I would be working outdoors all day on a Saturday and I'd visit my very little Perle d'Or. She'd have a dozen rose slugs on her. I'd squish them and go back to what I was doing. An hour later, I'd find nine more on her. On and on all day long. She had no leaves this spring. And it's a testimony to her wonderful spirit that she has two new baby canes this fall and is blooming her generous heart out.

Last year was horrible, our first year with lots of new roses. I hated to take close photos of the plants because of all the holes.

But this year we have wasps galore, too many for me personally, but they spend their days in the roses and flowers and suddenly, the leaves are mostly fine. I think I put nature out of balance with the influx of plants, the wasps are also out of balance this year, but bet next year the numbers reduce.

I realize I spend hours and hours on mulching, composting etc, but only minutes on the actual roses themselves (and that is usually just deadheading)

IMO, Schneider's warning observation should be taken as wise advice, whether the alfalfa used by the gardener is rabbit food or not. Any of the essential elements, when out of balance, can be detrimental to plant life; and trace elements, when they become more than "trace", can be every bit as toxic as the overuse of any one of the "big 3". They're categorized as TRACE elements for a very good reason.

BTW . . . I can't cite a specific source or authority at the moment, but Schneider is neither the only, nor the first to caution rosarians about the overuse of alfalfa.

I found this picture of Dr. Manners of a leaf manifesting boron toxicity. he says it is also related to a really low pH. I learn something all the time!

No one has answered your question of how much alfalfa is too much, and I don't know, but I thought something we could be on the lookout for is boron toxicity if we use alfalfa. Or if our pH is on the really low side.

Gean

Cath

All the treated roses were own root.

Cath

Cath, I have heavy clay too but have only been using alfalfa since this growing season. I have been SUPER happy with the results. Annalyssa, in her thread for suggestions on white and tall, asked me about my feeding regime and that was partly the reason I brought this subject up. I described to her the watered-down "smoothies" I made for my roses containing alfalfa as well as bananas, coffee grounds, and the occasional other ingredients such as egg shells and cooking water from vegetables. But I warned her that, as a novice, there might be drawbacks to my feeding methods that I wasn't aware of. In my garden, a week or two after I feed my roses with this concoction I am rewarded with beautiful new leaves, laterals, and very, very often promising shoots near the base of the rose. For me, this happens both on my DA roses grafted on Dr. Huey and my new own-root roses. However, you make an interesting point about the tea family. I have three teas so far and while I haven't noticed any adverse effects, I am somewhat inclined to say that mine have not responded as vigorously to the alfalfa smoothies as other classes. But I will have to monitor them a bit more closely with that in mind.

What I gleaned from Peter Schneider's comment was that in most cases it takes several years for the boron toxicity from alfalfa to occur. This worries me when I imagine nurturing a rose for four, five, six years until becomes the rose of my dreams and then begins to languish because I poisoned the soil through my ignorance. All day I have been wondering how much is too much and I wonder if one factor might not be what one's soil is like to begin with. I cannot begin to try to guess how the soil's chemical makeup plays a part-- the way they all interact is still beyond my grasp and may always be beyond my grasp but more like light, sandy soils may be able to flush the boron out easier whereas it might stick around longer in heavy clay like mine. I hope to hear more input. I am beginning to think my three or four applications a year could be "overboard."

For many of us we could not reach pH 4.9 with out replacing our soil.

Hi, Kippy :) Thanks for pointing that out. I hope someone can explain the relationship of the low ph and boron and alfalfa. I'd be delighted not to have to worry about it!

"Bugs always leave some to reproduce so there is always something to eat."

It seems to me that no one here has enough information on Sidos-House's specific situation and conditions to give advice on the use of alfalfa. Not only soil pH, but soil composition should be taken into account. It's up to Sidos-House to have a soil test/soil analysis. The amount of boron naturally present in soil varies radically from one locale to another, and that factor alone would have a significant impact on how quickly boron toxicity would impact roses. Drainage would also be a crucial factor -- as would any number of other cultural issues, including companion plants and/or other plants grown in close proximity to roses.

As regards this alfalfa question, I'm convinced that moderation is the key -- as it is with everything else in life. Many gardeners seem to assume that there can never be too much of a good thing. Its alfalfa meal in the planting hole, its alfalfa tea at regular intervals throughout the season, and -- just for good measure -- its more alfalfa meal and/or pellets scratched into the soil from time to time. And, more often than not, in addition to the alfalfa overload, there's all manner of other ferilizers, brews, potions and (of course) bananas.

Personally, I'm of the strong opinion that the real key to success is soil pH pure and simple. Maintaining the proper pH is every bit as important as applying fertilizers (or growth "stimulants" like alfalfa) -- and probably MUCH more important.

I live near Dayton, Ohio on what is called Miamian Soil. It is 8-10" of top soil with very heavy clay subsoil very high in calcium over limestone rock. the clay is deep enough that I have never encountered limestone bedrock on this property. This type of soil covers most of Ohio into Indiana and some of Illinois. The limestone is due to the fact that it was once covered by a sea which is evidenced by the trilobites found embedded in the rock.

I have not grown tea roses successfully. La Biche lasted 2 winters and the White Maman Cochet has lasted one. The winter was hard on it. It was about half the size in June that it had been the preceding fall. It may now be dead, possibly in part due to the alfalfa. I plan to try White Maman Cochet again but wait until it has filled a 5 gallon pot before I plant it out. I had bought a Devoniensis and the blooms were heavenly but sanity prevailed and I gave it to a family member in a warmer zone where it will have a chance to live.

As to pH: I sometimes mix peat with the soil when planting and do mulch with pine bark these help balance the alkalinity as does alfalfa. It is just that the WMC, in particular seemed to take a sudden turn for the worse after each application of alfalfa, not that she was thriving before the application.

Cath

There is an area of my garden, a terraced area, that has a pH of 6.3, which is perfect for roses, from what I read. I'd also been using organics only in that bed. Roses would not grow well in that area.

A soil test showed soil low in calcium and potassium, but the thing that really showed me why my roses wouldn't grow well there is the inability of the soil in that bed to hold onto nutrients, shown by the soil test as a CEC of 6.3.

I knew that water ran through the area quickly, but it hadn't dawned on me that nutrients were running through just as quickly and I needed to fertilize twice as often there as other places.

I have not used alfalfa in a couple of years as I couldn't tell there was any benefit to it. This year I also did not use any manure/fish emulsion and have switched to synthetics with shredded leaves/wood chips as my main organic mulch/soil additive.

The soil warms up here very slowly and it has been taking too long for the organics that worked so well in the south to become available to the plants. I owe Kim Rupert a debt of thanks for telling me that nitrogen conversion from organics is dependent on soil temps. That helped me understand why my roses weren't growing as well as I though they should in all areas of my garden. Here, air temperatures might not reach 70-75 degrees until the beginning or middle of July, much less soil temperatures. So I am experimenting with using synthetics w/my wood/leaf mulches for a couple of years to see what happens.

From looking at that chart that shows availability of nutrients at various pH levels, I can see that 6 to 7 pH renders most nutrients to roses available. The roses can't uptake what's not there, even if the pH is perfect. That sounds like a 'duh' lesson, but I have realized I need to be more conscious of making sure my roses get enough nutrients, taking into account how fast the soil leeches and the soil temperatures as well. In that terraced area it was sorely lacking in nitrogen and potassium, which leech quickly anyway.

I used almost exclusively organics of alfalfa, manure and wood chips in Alabama and found they worked well. Here, I have had trouble with that, because of the cooler temperatures, I think. There are a lot of variables in play and I am not sure there are too many hard and fast rules except that roses like to be fed and watered.

I found this on the Paul Zimmerman site and while it's geared toward the Washington DC area, there are some things I've been able to pull out of it. Maybe it will help some others, too, especially the guidelines on pounds of nutrients/8 month period and Appendix 2. All of it is interesting to think about, anyway.

P.S. I also mix in green sand and a little bone meal in the planting hole.

Cath

Gean, thank you! The link you've sent to Paul Zimmerman's guide is very interesting. I've saved the pdf so that I can use it as a reference. It has plenty of information that could be useful to anyone, anywhere. The feeding schedules and his later comments, too, are interesting as well as the duration of the type of fertilizer. I wonder if that duration is true based on the typical soil in DC or if it is more generalized. I'll have to look at the document and website more closely. I also enjoyed reading about your experiences. It's interesting about the soil temperatures and nutrient uptake. It makes sense once someone points it out but is not the kind of thing that would occur everyone. Not me anyway.

Thanks too, Jaxondel, for your comments. I completely agree with you about about moderation and, it's true, ultimately it's my personal responsibility to figure out how much is the right amount of alfalfa to use in my unique situation, as well as how many bananas, and what specific ingredients to include in the potions I brew for my garden! Still soil chemistry is a difficult subject for many of us and although we all have individual garden situations, it's nice to be able seek out guidance from those with more experience and knowledge. Thanks so much!

Paul Zimmerman, himself, though, doesn't use that plan. He uses manure with a wood chip mulch over the manure and I don't think does anything else in his garden. In his warm climate that works great for him. I wish it worked great for me.

I also don't think that my once bloomers need as much as the repeaters do.

Good luck with your garden; I have loved the pics I've seen of it. Gean

You have to be right about the once-bloomers -- they really have many advantages.

I'm addicted.

:)

Have a great week. Thanks, everyone.

You are very kind, Sidos. That was a very nice thing to say. This place is populated with a great many very kind and knowledgeable people. Gean

Kim-based on what we put in the green waste bin....I don't want it back.

One annoying caveat - it simply sulks when fed with sweetcorn or pea haulms.....but a three inch branch - no probs.

It's getting to that time of year when we run it almost constantly.

We definitely could use a chipper here with an acre and half of Wood. I'm glad you splurged on it, Gean. Maybe in a couple years, I'll be able to look into finding one too! And, Camp, from what I've seen of your enchanted Wood, you NEED a chipper. Perhaps even more than the pickup truck, thus spending more was absolutely sensible. :)

I hope your new chipper works out for you, Kippy. My neighbor did do some chipping for me of a bunch of cedar branches that we took down when we put up our deer fence. I used them in our fall kitchen garden hoping the cedar mulch would also help keep away the bugs from my little green things. .:)

As for sawfly, at this point I'm chiefly seeing it in potted roses and so far I have mostly ignored it. It will be time to replace the soil this winter (a truly dreaded task) which ought to deal with the problem for now. I hope so anyway. But I am just back from trip back east. I noticed that the two potted roses my sister has on her deck, 'Lullaby' and 'Little White Pet', had the kind of leaf damage I would associate with sawfly, though we could not find any actual creatures. I was at a loss to advise her as to what she should do.

Rosefolly

Rosefolly, as I've looked at the nutrient availability chart related to pH there's something else that happens with boron at high pH. I think I understand that at low pH plants uptake too much boron but at high pH boron become inaccessible so you get a deficiency. But I don't quite understand because at pH 9 and above it looks like it uptakes well again.

Here's a link to one of those pH nutrient-availability charts.

Thanks for the birthday wishes!

Anyway, thanks for the input, Michael, much appreciated.

Sidos, sorry for the way this thread veered off-topic . Gean