Sheesh, I never realized the chaos rust creates in the garden. I hope you can get a program that will help. It makes me appreciate our cold winters, maybe just a bit.

I am so sorry about your rust Larry, I hope you can get a handle of it...

The bog gets some shade but a lot of sun, during the summer probably a little too much sun. The original thought behind the bog bed was a result of all the drought years we have had in the past. The bog was a perfect solution to the watering problem. Now though, with all the rain we have had, more than I remember here over the fall, winter and spring things are just too wet. I did notice today even with standing water in many places things are actually drying out some, the forecast for rain over the next few days has been cut to us having a very little chance of rain. Do I think the problem with rust is related to the high humidity in the bog, you bet. It is just something that has been good for the past several years and is not so good this year. The constant water supply does make the plants grow very well, but it also seems to have a downside.

So sorry that you are having bad rust problems, Larry.

For what it's worth, the garden spots where I tend to get rust are mostly in the shade, or where irrigation hits the daylilies, or a combination of both.

I have also come to the conclusion that it is better to limit the garden to the more rust resistant plants per the ATP rust scores. Per the ATP database, a plant with a score of 2.4 is considered resistant, but a score of 2.5 is considered susceptible. I suppose that a line of sorts has to be drawn somewhere, but fwiw I am at the point where if I am considering a plant, and its score is greater than 2.1 or so, I won't get it, unless I absolutely have to have it for some reason or other (such as still rare tet poly genes). And I would prefer to get less than 2.0.... as in 1.5 or less, similar to Becky. (But on the other hand, I have at least one plant here rated a 2.0, 'Full Moon Magic', which has not had rust problems, and I have grown it for over a decade. It may be because it is planted in a sort of out-of-the-way spot, or it may be simply luck, or it may be a matter of different rust strains. So you can have some clean plants that are rated at 2.0, but I think the lower the score the better your chances.)

Of course the big problem with all of this is that most plants in the database don't have a decimal rust score, and new or recent introductions most certainly don't. Then you have to rely on people posting their gross observations in the database, as to susceptibility or resistance, and those could be wrong. One person's susceptible could be another person's resistant.

If I want to buy a new plant, I now (mostly) try to research its parentage to get some idea of its potential for rust. If it has rusty parents in the background, forget about it. By that reasoning, I will not now buy anything that has 'Wild Cherry Round Up' in its background. I have never grown that plant, and there is no rust score for it in the ATP database, but I have had too many plants with that as an ancestor, and every single one of them has been rust prone. WCR does not have a rust rating, but if you look at its parentage, it has 'Cherry Valentine' (ATP score 5.0) and tet 'Connie Burton' (ATP score 3.0) in its background. I would be amazed if 'Wild Cherry Round Up' were not a rust bucket (in those gardens that were not sprayed, and had active rust).

You can take this principal and extend it to sort of work out your own (half baked) way of estimating rust scores for plants for which there is no data. Trace the heritage back, using ATP scores where available. If no numerical data is available or can be contrived (for an unknown or seedling parent, for example), you can use a 2.5 (borderline resistant/rusty, tending towards rusty). If you have personal observation or experience of an ancestral plant being rusty, you can give it a gross estimation score (say, 3.0) and use that, if that plant appears in the ancestry. Ditto for a plant you have that is resistant (maybe give it a score of 2.0).

(Yes, I realize that some resistant plants derive from rusty parents, and vice versa. I also realize that while such a half-baked score might apply to a large population of children for a potential cross, it is an average and may not apply to any particular individual plant. But faced with a buy/no-buy decision, and lacking direct information as to resistance/susceptibility, I have resorted to this type of estimation to help make my buying decisions.)

I worked out some of these half-baked scores for some plants that I have, and the results were interesting. I will give a few examples:

WINNING NOTE = MEADOW SWEET x TOTALLY TROPICAL;
............................................MEADOW SWEET has an ATP score of 1.0 (resistant, yay)
.............................................TOTALLY TROPICAL has no parents listed, therefore it is assigned an arbitrary score of 2.5
The average score of the two comes to 1.75, still resistant. And that has been my experience of this plant, thus far.

POLLY WOLLY DOODLE = sdlg x BILL NORRIS;
.........................................................sdlg is an unknown, so we give it an arbitrary score of 2.5
.........................................................BILL NORRIS is susceptible with a score of 3.0.
The average score comes to 2.75, or susceptible. (And thus, sadly, has been my experience.)

HIP TO BE SQUARE = BILL NORRIS x ED BROWN;
...................................................BILL NORRIS is susceptible at 3.0
...................................................ED BROWN is resistant at 1.3
The average score comes to 2.15, or slightly resistant. (HIP TO BE SQUARE has shown to have a surprising amount of resistance in this garden, much more so than the score would suggest. So the score is a ball park estimate.)

As a cautionary example, sometimes this estimation procedure can be way off base:

OSTERIZED = YELLOW MAMMOTH x GREEN DOLPHIN STREET
.....................................YELLOW MAMMOTH = HUDSON VALLEY (susceptible, so assign it 3.0) x MONSTER (assign 2.5);
.....................................The average score I would predict for YELLOW MAMMOTH would be 2.75
.....................................GREEN DOLPHIN STREET had significant rust in my garden in 2006, so on the basis of personal experience, I gave it an arbitrary score of 3.0.
The predicted rust score for OSTERIZED would be (2.75+3.0)/2 = 2.875, or rusty. Yet OSTERIZED has had good resistance here, in the face of shade, irrigation spray, and heavy rust pressure. (As I said in another thread entry, I would recommend this plant to anyone.)

One of my pet peeves is that so many near-white daylilies are rusty, so I wanted to try to find some plants to use to produce seedlings that perhaps are not so rusty. One possible purchase was WHITE PERFECTION. Let's see how it works out:

WHITE PERFECTION = ARCTIC SPLENDOR x WHITER SHADE
...................................................ARCTIC SPLENDOR = sdlg x Tet GENTLE SHEPHERD; In the face of no data for either of these parents, I assigned ARCTIC SPLENDOR a score of 2.5
...................................................WHITER SHADE = PTARMIGAN x Tet HOMER HOWARD GLIDDEN
.................................................................................PTARMIGAN = ARCTIC SNOW (2.3) x WHITE TIE AFFAIR (sdlg x Tet IRON GATE GLACIER, no parentage); assign WHITE TIE AFFAIR an arbitrary score of 2.5, which gives PTARMIGAN a score of 2.4
..................................................................................HOMER HOWARD GLIDDEN has a score of 1.0
....................................................The estimated score for WHITER SHADE is (2.4 + 1.0) / 2 = 1.7 or resistant
The estimated score for WHITE PERFECTION is (2.5 + 1.7)/2 or 2.1.

Normally a score of 2.1 would make me hesitate. But as I have said, I have had at least one plant here with a score of 2.0, that has thus far been resistant. (Or maybe just uninfected. )

Given that so many near-white tets are so susceptible to rust (by my estimation, ARCTIC LACE is 3.0 , VICTORIAN LACE is 3.53, as two examples), even 2.1 is an improvement and a step up, so I bought the plant. (It is literally a brand new plant, so I have no garden data to give on it.)

This type of half-baked calculation can also be used when projecting crosses. If I have a seedling that I like enough to keep and work with, but I want to improve its rust resistance, I do the same sort of calculation. I have a seedling here which I believe (don't ask me why ) is from a cross involving COYOTE MOON and ONE FINE DAY. The seedling is somewhat susceptible to rust, but not nearly as bad as COYOTE MOON (score of 2.9). (The seedling was hybridized in 2005; I had not been hit by rust then (not until 2006), so I had no rust data and therefore no method of predicting that maybe the cross would not be a good one.) ONE FINE DAY has a score of 1.0, so the calculated estimation for the seedling is 1.95. (I think it is rustier than that...) I crossed this seedling back to ONE FINE DAY, the seedlings from that have an estimated score of 1.475, and thus far they seem to have good resistance.

Maybe this kind of approach will be useful to some people here, both in purchasing and in hybridizing decisions. Just be sure to keep in mind that any particular individual plant or seedling may behave better (or worse) than what you might predict for the cross, on a whole.

edited to clarify the situation with the 2005 seedling

I found this article on spray programs but it seems to involve a lot of chemicals to rotate between. I would like to be able to limit it to only a couple if possible. Do the chemicals suggested for the home gardener have much effect on daylily rust, and can the control chemicals used by commercial growers even be purchased by the home gardener?



https://www.scottelliottdaylil...

Arggh, Larry, I clicked on your link, and that horrid picture popped up with the rust pustules RIGHT IN MY FACE!

It's too early in the morning to face such horrors...(for me, anyway...).

Last night I started working through the lists of plants currently present in the garden, doing a rust score estimation (in the absence of ATP decimal scores). It was surprising the number of plants that I had bought on the basis of rumored "stainless steel" resistance (as mentioned on one site or another) which scored over 2.0. 'J. T. Davis' got a score of 2.125, and I have to say that it's looking rather sketchy at the moment.

On the other hand, one plant that I was considering pitching for reasons other than rust (or leaf streak), scored pretty well with a 1.6. I've been of two minds on that plant for several years now. At one point I had yanked it out of its pot and left the whole clump to dry (and hopefully die.... the roots were packed so solidly the easiest thing to do seemed to be to let it decompose)... but I left it in the shade and that apparently gave it enough of an edge to survive. When I saw several months (a year?) later that it was still alive, I told it "okay, since you want to live so much...". But just a few weeks ago I had made up my mind to toss it again. (The foliage always looks horrible early in the year... maybe with what is called "spring sickness"? And the flowers, while having a gorgeous color, have some form problems.) What's a girl to do?

Seedfork said:I found this article on spray programs but it seems to involve a lot of chemicals to rotate between. I would like to be able to limit it to only a couple if possible. Do the chemicals suggested for the home gardener have much effect on daylily rust, and can the control chemicals used by commercial growers even be purchased by the home gardener?

Larry, this article has some suggestions that may be easier to follow for the home gardener:

http://www.daylilies.org/RustR...

Note that in the article in your link there is an error in the table of active ingredients. Compass is not pyraclostrobin, it is trifloxystrobin. Pyraclostrobin would be Insignia, Cabrio, Headline.

Polymerous, do you have a picture of your daylily with possible spring sickness?

Sorry Sue, no.

I just e-mailed the county extension office and I will see what they suggest. I do appreciate all suggestions and I am reading up on chemical rust treatments.

A sort of update on the Serenade treated plants. I can't tell if the Serenade has stopped the progressive spread of rust, or not. The rust which was sprayed did turn all tan and brown... which was not a big visual improvement. So yesterday I started pulling leaves... lots of leaves. I filled up one of those large plastic lawn bags full of leaves. There is still more to do. I should do another round of Serenade, but I couldn't get to it today. (I'm still trying to get the rest of my kitchen garden in, plus I got sidetracked into battling some weeds which have taken over certain parts of my side yard and kitchen garden raised beds. These weeds must have come in with compost or mulch maybe 5 or so years ago now, they look sort of like individual grass plants, and while their numbers have thankfully diminished, I've been unable to get them all out. They invaded my garlic chives and I've been battling that spot in particular for the past 5 years; today I said to heck with it, time to sacrifice the chives and dig that bed up and throw away dirt as needed. Those weeds must go!)

Off in the (older) seedling bed, a bit of rust had started spreading. The initial culprit was the sole seedling from 'Reason for Treason' (not a surprise I guess, as 'Reason...' had some heavy rust over a year ago which got it booted from the garden). About 4 of the adjacent seedlings were also showing some rust, in varying degrees. I yanked the foliage. (I would have yanked the worst plants, but the drip grid hampers that.) For now, I think I am going to have to be satisfied with keeping the foliage cut and then sprayed with Dawn or Serenade, and generally keeping an eye on that bed. Being on drip (versus spray) irrigation will help once it warms up and gets drier here... I hope.

Yep, time to look for more 1.0 Rust Score plants...

Well, I will update my rust problem here also.I mixed up a concoction or dish detergent, Immunox, and Daconil .
I have sprayed twice with that, plus I have pulled a huge amount of leaves. I would say the garden looks 80 percent better! However, mostly because of the rusty awful looking leaves being disposed of. I do think the spray has done some good also. But, I actually believe the main reason the garden is looking so much better and is showing such a decrease in rust is largely due to the weather change,.We have had two weeks of dry weather with just a few sprinkles on just a few days mixed in. Now the weather has turned cool again for the past few days and this morning actually felt chilly. I am really surprised by the sudden turnaround in the rust situation. I think as the rust progressively moved from plant to plant I could envision the entire garden being a huge rust bucket, but hopefully with spraying and by pulling so many leaves and by having a lot of plants that do at least show resistance to the increase of rust, the progression of rust can at least be slowed down and kept at an acceptable level.
I am not very confident with my spray program , and I am still waiting a reply form the extension service to my e-mail. I will admit though that I do feel spraying could have had much more effect than I give it credit for, I just have no way of knowing what the actual reason was for the sudden improvement in the looks of the garden. I don't have a gauge for how fast spraying improves the decline of rust? Does anyone know if it is a next day, next week, or just how long it takes to normally see a much reduced amount of rust in the garden?

Polymerous said: I got sidetracked into battling some weeds which have taken over certain parts of my side yard and kitchen garden raised beds. These weeds must have come in with compost or mulch maybe 5 or so years ago now, they look sort of like individual grass plants...

Sounds like a real nightmare. Do you have any pictures of it? What kind of 'flowers' does it have? Is it coming from a bulb?

Does anyone have experience with Green Magic? It's sold as a degreasing cleanser that is also supposed to work on rust.

Larry, sorry that I don't have an answer for you.

Ken, I don't let it get to flowering stage! It's like a weedy grass, but it is somewhat fine bladed with sort of sharp edges and maybe a bit of a midrib iirc (not going out into the wet to look around for any I missed), and the basal foliage is purplish red. They have real roots, no bulbs. And what seems to be happening, is that if you leave even the tiniest bit of root behind, it keeps coming back. Earlier this spring I thought I had beaten it in one of the beds, but nope... I found a bunch yesterday. My best guess is that it is an invasive perennial, but I have no guess as to whether or not it is a native (because the presumed source of it, compost or mulch, could have come from who-knows-where). I looked at the Calflora images, but they weren't helpful. Maybe next time I am out with a camera, I will think to try to take a picture.

Leslie - There was some mention of Green Magic in a previous thread: The thread "Daylily rust" in Daylilies forum

Thanks Becky!

Well, I am discovering something as I am growing about some of my seedlings .....

Many of the pretty faces seem to have low rust resistance.....

Dragonfly Dawn (one of my favorites!!) does show less than desirable rust resistance. I think every seedling I've grown from it as a parent shows some degree of rust. (Several of my seedlings are DD x DD crosses.) Most are in the 2.0 -3.0 range. Which is discerning for me because I love, love, love that cultivar. Now my direction will be to cross some of the children with highly rust resistant cultivars (or seedlings) to maintain a pretty face AND better rust resistance.

I am also finding that a number of spider cultivars that are used as parents are showing fairly good rust resistance. I don't know if the thinner leaves has anything to do with that or not. But that has been very encouraging to me!

I am NOT yet discouraged from my favorite pretty faces, but I do keep in mind whenever I acquire seeds, that I must lower my expectations of some of the more attractive blooming cultivars! It's going to take crossing them with some highly rust resistant cultivars (or some of my good rust resistant seedlings) to make them more acceptable to me to create nice foliage and the lovely blooms I really want .... without a chemical treatment program .....because I will only grow organically.

The following are some observations, in no way scientifically rigorous, but I give them as food for thought, as to what it is going to take to clean up the rust buckets. (The status of my two F2 seedlings is clearly subject to downgrading at any time, and to get a better evaluation, the F2 seedlings need to be moved into the rustiest part of the garden.)

I have an old seedling (my avatar shows its bloom) which I believe (label issues) came from a cross of ONE FINE DAY and COYOTE MOON. (Don't get excited by the polymerous bloom... it only did that one season, at about 20-25%, rarely since then, and has produced no polymerous offspring.)

ONE FINE DAY has an ATP rust score of 1.0 (as good as it gets for resistance), and has been outstandingly resistant here. (It dwells in a lot of shade, and has been exposed to heavy rust pressure last winter (2014/15) and this winter (2015/16).)

COYOTE MOON has a rust score of 2.9, and I have battled rust on it last winter and currently. (It lives in the same side yard as ONE FINE DAY.)

The seedling is also somewhat rusty, but seems somewhat less so than COYOTE MOON. (Ditto same side yard, lots of shade, yadda yadda. Note that this is a subjective and not objective evaluation, in that I am not counting rust spores or rust patches. Moreover, it took some years for rust conditions to evolve in the garden to the point where the seedling could get infected. The lesson here is that it may take several years and the right conditions to accurately evaluate any seedling. Since we all (presumably) have limited space in our seedling patches, that effectively means that we must cull out all but the least susceptible seedlings (to have room for the next year's crop), while leaving space to monitor those remaining seedlings for some years (or deliberately expose them at a young age to heavy rust under the right environmental conditions) , to get an accurate assessment.)

Getting back to the (presumed ONE FINE DAY x COYOTE MOON) seedling, I crossed it back to ONE FINE DAY and currently have two seedlings from it. (I'm not sure if I ever planted out any others... I do have issues with % germination and keeping young seedlings alive. )

Those two seedlings have both, thus far, shown good rust resistance (as in, I haven't seen any rust on them, yet, and they get watered with a hose sprayer, which would be conducive to rust, and there have been some rusty plants nearby). Those two seedlings do NOT dwell in the side yard; they currently reside on my patio, which has more sun than the side yard areas. While there has been some rust exposure there, it is not as much as in the side yard. If I were to be more rigorous about my evaluation, I should move the seedlings to the side yard, preferably right next to COYOTE MOON, and let it drip rust all over them. I may yet try that (one plant would have to be potted up from a tree pot first), but I'd rather enjoy the flowers on the patio. (The seedlings have small yellow flowers; I like yellow daylilies. YMMV.)

The point of all this is that one generation of crossing, even with a very resistant cultivar, isn't going to get you where you want to go. It is going to take you at least two generations (using 1.0 resistant plants in both generations of crosses), and probably more. (Almost certainly more if you do sibling crosses on the F1, rather than crossing to a 1.0 cultivar. More generations if the susceptible plant is worse than 2.9-3.0. More generations if the resistant plant has a higher score than 1.0.)

AND you have to give the candidate seedlings sufficient time and/or sufficiently rusty garden conditions (the worst rust micro-environment in your garden) for evaluation.

For what it's worth, using my half-baked rust prediction method...

ONE FINE DAY = 1.0
COYOTE MOON = 2.9

F1 sdlg = 1.95 (which should be "resistant" on the ATP 1.0-5.0 spectrum, but the seedling isn't my idea of resistant (no, I don't evaluate degree of susceptibility rigorously, as in counting rust patches per inch))

F2 = (F1 x ONE FINE DAY) = 1.48 the seedling should have some good rust resistance, but it could be better

If I were to take it a step further, and cross the F2 back to ONE FINE DAY (again):

F3 = (F2 x ONE FINE DAY) = (1.475 + 1.0)/2 = 1.24 slightly improved resistance (In practice I would not make this cross; ONE FINE DAY has a low bud count here, and the bud count on these two F2 seedlings already leaves something to be desired. If I wished to continue playing with these two plants, I would either outcross to something resistant that would jack the bud count back up (while retaining the early bloom season and bloom opening traits), or I might do a sibling cross, hoping to recover a higher bud count from the F1 sdlg genes.)

If I were to sibling cross the F2s, I would guess that the F3 seedlings would have on the average the same resistance as their parents, but there might be some that are rustier, and some that are more resistant. (However, I might also recover some of the bud count and branching from the F1 sdlg, which got it from COYOTE MOON.)

So from just these few seedlings, you can see that we have got our work cut out for us, cleaning up the rust buckets. Since it's going to be a lot of work, we need to pick our battles wisely. Be certain that whatever plant you are trying to rescue (for whatever features you deem desirable), that X generations downstream it is going to be worth all the time and effort: you will have retained or enhanced the things that you loved about the original plant, retained or enhanced the bud count, branching, flower substance, flower opening, season of bloom, and have gotten rid of the propensity to rust (to the extent that any of us can, with multiple strains circulating).

javaMom said:
The daylilies .. in the raised bed...... I don't know how deep I have to plant those...

Hi. I agree with the comment that rot is the worst, in that once it starts the plant is history. I must have repotted ARABIAN MAGIC a bit too deep as it rotted not long after flowering. We had had a lot of rain. But others were fine. I once lost 2 separate DOUGLAS LYCETT plants to rot, probably from accidental overfeeding. My soil is very heavy, but generally on a slope so there is good drainage. I try not to plant things deep but have a lot of 'pine straw' as mulch. However, I have a few growing very well where it can have an inch of water standing for a few days. I think some are more susceptible to rot than others.

It might be a while before your plants need thinning out. The light clay soil would hold moisture which can be a great thing unless it rains in buckets for a few days at a time. Gypsum or claybreaker works well on my clay-shale subsoil. Magic. It actually turns it into nice crumbly loam.

I hate rusts and recently had it on a gladioli. So I will try detergent spray to see if it works on gladioli rust. Some right next to it don't have it. I too find it helpful to remove rusty leaves. I recently ripped off all the rusty leaves of my frangipani (plumaria). They are deciduous here anyway.

So far I have not discarded daylilies. My rejection criterion may be "the scape developing pustules". The plants manage without a few leaves but I see no point growing them if you have to ditch the flower stalk. I ripped heaps of leaves of this HURRICANE SKY after I took the pic.


Luckily we are having a dry cool spell so the plants can muster some strength after so many blow torch days.