Sadly my some of daylilies had rust.
After spraying and with weather getting hotter, I think it is receding for now.

Some leaves were trimmed off, but the plants look a little raggedy.
Is there any that can be given them to boost their appearance/health at this time?

When should spraying start for the Fall round of rust?

Thanks for input.

Bumping this up.....

I'm sorry to hear that your daylilies had rust and to see that we have had no answers for your questions yet. We do have members from areas where rust is prevalent and of great concern. Hopefully one of them will see this and be able to answer your questions shortly.

I don't really have a good idea for this but I'll outline what I normally do. I cut a couple back to 2 inches and sprayed for rust yesterday. These were new plants shipped north this spring. I just give them adequate water, sun, and if I have it, compost tea. If not, I wait until they are showing signs of growth before putting normal fertilizer on them.

I hesitated to respond because I have not had rust, but I know that James' directions for cutting back daylilies to near the crown is also shown (with pictures) on Sue Bergeron's rust site, and have been described elsewhere as tried-and-true standards for how to approach it. http://web.ncf.ca/ah748/newpla...

However, I have often wondered about more resistant cultivars if, after trimming away just parts of the leaves that show rust, any remaining leaf areas might respond to a spray of mild liquid dishwashing soap and water, as the plant recovers.

There was a study done at the University of Guelph in Ontario, Canada (supported in part by the AHS) in 2004 that is also linked to Sue Bergeron's site. I don't know if further research there or elsewhere has found new or contradictory information but they reported that "Among the contact fungicides applied three days after inoculation, the dishwashing liquid was able to reduce rust development to a level not significantly different from that of the systemic fungicides". Perhaps @sooby would be able to update, comment further, or explain if that would not have any helpful application after rust has already appeared (and whether it is a worse course to experiment than cutting back fully).

http://www.uoguelph.ca/~thsian...

But, since I use a mild soap and water spray to combat aphids, and find that it also improves the look and vibrancy of the leaves here, that is what led me to wonder if daylily plants that are only mildly impacted with rust (resistant to the rust) could still do well with some foliage intact.

Maybe if you have extra fans of a more resistant cultivar that is showing less rust, and at least two areas where they are located, so that you would not lose all of your cultivar by trying it out ... I wonder if it would be worth spraying mild soap and water on one set of the fans to see if they might do okay and still look pretty good in the garden, without having to cut them all the way back (or spraying and alternately rinsing, to keep the soap layer from building up and impeding respiration of the leaves)?

I'd guess rust is a bigger issue than we really want to think about.
Especially since I've read it can travel 60 miles carried in the wind.
It really makes plants look bad. Poor babies.
Like how could you talk anyone into buying daylilies when rust has beat the stuffing out of them?

I did cut back, but read that cutting back shouldn't be continued past a certain point.
I have sprayed although I haven't used the systemic spray I just got. Right now, high temps have slowed rust down.
For general info, I found organic contact sprays to be more effective than some of the more un-organic ones.

I suspect rust came in from a NC grower and those plants fared the worst...looked like they were going to die.
And it spread to my other new plants that I've been trying use for hybridization.
Amazingly seedlings weren't much affected and my older plants that have been here for ages didn't seem to get hit that much either.

I guess the good thing about getting rust while having a new interest in daylilies is that issue can be addressed and dealt with.
Indoctrination this year has been pretty good: fungus gnats eating seedlings, leaf streak, and now rust.
On the plus side, there are oodles of big seed pods out there and hopefully, they won't be sterile.

chalyse said:different from that of the systemic fungicides". Perhaps @sooby would be able to update, comment further, or explain if that would not have any helpful application after rust has already appeared (and whether it is a worse course to experiment than cutting back fully).

Sorry, no there was no continuation of the Guelph study. I'm not sure what to suggest to improve appearance. You can't reverse leaf damage that has already occurred so other than picking off the worst leaves or cutting back the plants so that they grow a fresh set (which one probably wouldn't want to do more than once) I can't think of much that would help. The drastic trimming pictured on my rust web site is aimed at new arrivals, to limit the risk of bringing rust in on new plants to a garden that doesn't already have it. One possibility, any fertilizer to encourage new growth should probably not be high N and should have adequate potassium as these, particularly the latter, may have an impact on rusts.

There's been no research that I know of as to how far daylily rust specifically can travel on the wind. Some other rusts' spores can travel considerable distances. Both times I introduced daylily rust to my garden deliberately it didn't move beyond the main bed where I started it. There were other daylilies about 100 feet or so down-wind but they remained rust free so this is something of an unknown at this point.

Interesting, Sue.

I'd imagine rust could also be carried from one plant to another by the gardener.
I read it can be carried by wind, but don't have that source right now.

Some of my plants were side by side with the rusty ones, but didn't get impacted so much.

What do daylily sellers do when they get rust? Do they soak plants prior to shipping?
Would a 10% bleach solution be adequate to help prevent rust from being shipped (after plants had been treated with a systemic and looked clear of rust)

If we keep stopping or preventing rust, will daylilies ever develop resistance of their own?
For sure, it makes poor flowers look a mess.

Xenacrockett said:
What do daylily sellers do when they get rust? Do they soak plants prior to shipping?
Would a 10% bleach solution be adequate to help prevent rust from being shipped (after plants had been treated with a systemic and looked clear of rust)

I can only speak for myself but what we do normally here is after they are washed then they go into a bleach solution to soak while I wash the next plants. We don't do this for rust because I don't know that bleach will kill rust spores, we do it to kill anything else that may want to start lurking in a dark, damp (if plants weren't completely dry), hot box like mold. I have gotten boxes in and the roots had started growing hair (mold) but then I just soak them in bleach solution before planting.
What we did last year was we would dip the plants in rust fungicides after the bleach bath if AND ONLY if it was getting close to spray time but if I had just recently sprayed then we wouldn't. This was in the fall when it was getting close to the rust's normal time to breakout. One reason I stopped doing it was because I have to bring my plants home to box up and ship since I do not live at the garden and I have no place outside to do it so I bring them inside the house and the house would spell like chemicals forever and that wasn't good. Plus it was very difficult trying to box daylilies with chemical gloves on

I don't think most sellers soak there plants before shipping because if they spray regularly then there really is no point in soaking them and with bleach not being a known spore killer then why do it. If a daylily has no visible rust but is infected with rust (remember it is on the inside of the plant if it is) then the bleach really would do nothing for it since it cannot get inside the plant.

Pat, firstly if you got rust, you got rust. Don't pine for the nice looking foliage of the land of the dormants.

There are good recommendations for spraying and managing rust here in the ATP threads. But I assume you have worked out what to do there.

I am quite sure my rust came in on bought fans. One day the ugly orange pustules were just there. I look at other daylilies on this island - the few I can find: no rust except my place. Just attend to your garden is the best. Don't worry about down the road. Rust might never sleep but I don't think it is whizzing between gardens on rollerskates

What I do is periodically trim individual leaves on fans that are unaesthetic and I always remove dead leaves. Gone are the days when sellers say daylilies are self-mulching. I burn all these leaves. If you cannot burn, put them in a sealed plastic bag for the rubbish dump. However, with rust buckets, you can sometimes only trim so much before they are chlorophyll-challenged.

So

1. I spray.
2. I do not trim leaves more than what makes a clump look nice and green to the eye. This effect can last several weeks.
3. With rust-buckets, don't overdo the trimming.
4. Just fertilise and water as normal because you are not hacking into your fans.
5. If you are disturbed by all the chemicals and spraying, I think you should seriously consider mulching the rust buckets or giving them to neighbours or relatives you dislike.

Thanks, Michele.

Interesting, Glen.

I'm thinking some of the plants contacted the rust from the NC plants because they were new and stressed also.

I got more into daylilies looking for a way to help pay property taxes and insurance costs that increase each year.
I'm kinda stuck here on these acres; selling and moving is not an option unless I win the lottery.

None of my old plants EVER had any kind of problem other than me neglecting them.
So daylilies with issues is new to me and I appreciate all the help.

The practices that Sue (Sooby), Michele, and Glen outline track with information in the linked article, since even the chemicals used to suppress rust do not kill it, and an infection that is not yet visible at the time of digging and packing can take, based on what I read of the article, two weeks to two months before it erupts (longer than fans could be kept and watched before shipping). What was new is Sue's information about fertilizers and rust, expanded upon below in a follow-up post by her. They are very helpful details to learn.

Regarding resistance, there hasn't been any research I've heard of that indicates daylilies might be able to independently develop resistance to rust on their own. Scientists continue to recommend that cultivars chosen for hybridization include rust resistant parentage as the means for passing resistance on to offspring. Studies done in the first fifteen years following the discovery of daylily rust found that of over 800 tested cultivars observed in university experiments, over half were observed to be resistant.

So, there is a wide range of impact and response to rust infections - and those hybridizers who do not suppress rust have a built-in chance to observe seedlings' performance with rust in their own nurseries. Those who do spray may also rely on external test gardens that have rust to ship out seedlings and get informal reports back about their performance. Following the consistent advice of rust researchers, hybridizers who include rust resistant cultivars in breeding choices will be selecting for increased chance of resistance in offspring.

Spores can be mechanically transferred, but the study linked above also observed that spores appeared to be less likely or able to spread between plants that were between 7-33 feet or more away from a source of infected foliage. High temperatures (104 F) in a greenhouse also seemed to suppress rust development, but did not stop it from progressing once the cultivars were moved outside to lower temperatures.

Oh, and in regard to Glen's #5 suggestion, I'd like to go on the list of disliked relatives (as if I'm not already lol) to get rusty fans sent rather than just discarded! California only prohibits potted plants from coming in due to soil-borne pathogens, but has no restriction on rusty daylilies as long as they are shipped as bare-root plants. Since I am a home hybridizer, it would be most helpful to me to have a rust source to maintain within at least 30 feet of any seedlings.

It would be really hard for northern hybridizers to breed for rust resistance unless we have some sort of source indicating which daylilies are more prone to rust. We don't get much rust in the north so how would we know which daylilies are resistant or not???

There are averaged scores from various university studies and user reports on the over 800 registered daylilies that were exposed to rust and examined for performance, and those can be searched in the ATP daylily database: http://garden.org/plants/group...



To pull up all daylilies that have either been in averaged-score studies, or have been reported informally by ATP members, as having a resistance or susceptibility to rust, toggle the "shows resistance" or "shows suceptibility" box shown in the above screen-capture. For very specific university-based averaged scores that are only assigned to those cultivars that were formally observed and tested, you can also search via the numerical toggle. Those score ranges and test sources are explained and shown in a link found at the bottom of each daylily page ("Read our note about daylily rust scores" link):



Another approach is to search back on daylilies' lineages, as well as forward into their offspring, to find related lines that may have contributed to, or follow from, those that carry tested score reports.

I think most of the questions have been answered, but just to elaborate on a couple of points - yes rust spores do travel on the wind but what we don't know is how far. This would depend on the weight of the spores and the environmental conditions at the time (such as how high they were able to get in the sky etc.). Anything, animal, bird, shipping, rain splash, gardener, tools, insects that can carry spores from one plant to another can potentially spread rust as well. In areas where daylily rust is endemic then wind blown spores from elsewhere are more likely, where daylily rust isn't endemic then one of the other methods (usually new plants from elsewhere) is likely to be the source.

Indeed older daylilies didn't have the problem in the past because daylily rust didn't exist in North America before around the year 2000. That doesn't mean they wouldn't get it now if exposed to it, genetic resistance is a cultivar by cultivar thing and even daylily species can be susceptible.

In a garden rust can affect some plants badly yet not affect adjacent plants as much or at all. This most likely comes down to differences in genetic resistance and/or differences in the immediate environment from cultivar to cultivar.

Regarding my nitrogen and potassium comment above, what I was trying to say (not very clearly, sorry) is that if you're going to fertilize to encourage new growth after cutting back it may be advisable to be careful with levels of these nutrients because they may influence the severity of rust. High nitrogen can increase the severity of obligate parasites such as Puccinia rusts and potassium decreases the severity (according to Marschner's Mineral Nutrition of Higher Plants, Academic Press). This is a generalization for rusts, however, not specific to daylily rust so just something to think about when making decisions (also depends on existing soil nutrient levels).

Individual cultivars aren't likely to develop resistance to rust over time although resistance to different races (strains) of rust isn't necessarily the same. In other words a cultivar may be more resistant to one race of daylily rust than to another one. There is such a thing as systemic acquired resistance (SAR) but getting into how that might interact with rust resistance genes is beyond my level of knowledge. Nutrition is also a potential factor, as are environmental conditions. You may get more rust in a season/year when environmental conditions favour the rust and less in another year when conditions work against the rust. This may give the appearance of changes in resistance that actually do not exist.

Edited for grammar.

Most appreciative of the ever-informative and readily grasped information. I'll go back to edit down my mis-read on fertilizing - your detailed explanations help so much!

That's interesting, Sue.

As it turns out, it could be the older plants had the benefit of mineralized soil to their advantage.
They had been accidentally overloaded with Ocean Solutions last year when I started to pay attention to these long neglected plants.
Then they got Milorganite and Epsom Salts. This year, they got Fertrell Organic which contains green sand, kelp, etc.

I think I'll keep using Fertrell organic fertilizers since they last about a year in the soil and would prove to actually be cheaper in the long run than those hose-end types.

I looked for potassium at Lowes today, but couldn't find a good source. Wood ashes?
Have lots of oak logs that can be burned for ashes.

Marschner's Mineral Nutrition of Higher Plants sounds like it might be like the Albrecht Papers.
I think I got caught up in the moment and stopped using strictly organic when mineralization might be a big part in the answer in building stronger plants.

But I think this rust issue throws a wrench into marketing daylilies to landscapers. I've not seen any used around here.
And if they get rust and look terrible, chances are they won't be used.
Those of us who love them may be willing to take care of them through thick and thin.
But others, maybe not so much.

Daylilies are very common in our area, though we have such dry conditions and extended droughts that it is possible rust has a harder time taking hold.

But, there are so many rust resistant varieties, that even here, that is what landscapers use. I think many civic places (parks, medians, public buildings, etc) have narrowed their choices over the years, but with so many that have a track record for resistance, there's quite a variety to choose from. Gold edges, complex eyes, tets, dips, small and tall ... they are all represented.

Everything here in the way of landscaping in civic centers and other public access facilities is Knockout Roses right now it seems.
I haven't seen the 1st daylily used yet.
Would like to see that changed for sure.

You just gave me a bit of goose-bumps ... perhaps you might become the one to create a resistant line that could change all that for your local area!