Daylilies forum: Rust and Summer Dormancy

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Name: Donald
Eastland county, Texas (Zone 8a)
Region: Texas Enjoys or suffers hot summers Raises cows Plant Identifier
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needrain
Sep 21, 2016 1:52 PM CST
Maryl said:Just an aside to those about the sale of Maryotts to Schreiners Iris. I just ordered some Iris from Schreiners the other day and asked them about the daylilies. They haven't gotten the first batch in from Maryotts yet, I'm presuming because he's still taking orders. Since I'm concerned about rust I asked them how cold they got up in Oregon (pretty much knew the answer already) and it's not cold enough usually to kill existing rust. I know the one time I talked to Bill he said his area too was not cold enough to kill rust. So, if he has rust (and I know he sprays for it), it will go along with his plants to Schreiners.
Whether they plan on spraying for it or not I don't know. Some may not care about that, but others may be interested ............Maryl


I know you've said you've had rust imported in a season, but is your location cold enough to kill rust over winter? Never? Occasionally? Most of the time? Always? Just curious. I think my conditions might be similar to yours except you are going to get colder more often and with lower low temps. I've kept watching for rust because I haven't been concerned about where the plants are grown. I'm sure in the warm months it should flourish here much of the time. So far it hasn't. I've wondered if the heat dormancy the daylilies endure here might also retard the growth of rust, but I haven't seen where that might be the case.

Donald
Name: Maryl
Oklahoma (Zone 7a)
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Maryl
Sep 21, 2016 7:46 PM CST
Donald: The one year I had rust, the fall before I had received my first and only order from Maryotts. We had a mild winter, so all the green was not lost on their daylilies over that winter. However, and this is a biggee, in all fairness to Maryotts, the next spring I ordered from Carpenters in Texas , and two weeks after the arrival of their daylilies, one of them began spotting. So I think in all probability the rust came in on the Carpenter daylilies, but I couldn't swear to it as the Maryott daylilies also spotted pretty quickly......Our winters are erratic. Last winter was a warm one and had I had rust, I'm sure it would have overwintered and popped up this year. The winter after I got rust, by the grace of God, it was exceptionally cold - going down into the single digits, so any rust left over after I pitched all the obvious offenders, was killed. Because I can't count on our winters being cold enough I try to be extra careful about who I order from. I watch the weather over winter at the nurseries I patronize in Zones 7 -8 , and if they had a warm winter (again, like last year) I will not order from them that year. Also if they are northern nurseries I make sure that their daylilies are grown outside, not in a greenhouse where the rust could survive..........As to the heat stopping the spread of rust, I've heard the same thing myself, but my summer of rust we were well over 100 degrees for weeks and weeks and the rust never stopped. The blackspot on roses did, but not the rust. I would have to see factual data on this statement before I'd accept that as written in stone. .......I was lucky for many years not getting rust from the marginal zones, but rust has spread across the country now, more so then when I first started buying daylilies, so the odds of getting rust has increased. All I know is that I sure don't ever ever want it again........Maryl
Name: Donald
Eastland county, Texas (Zone 8a)
Region: Texas Enjoys or suffers hot summers Raises cows Plant Identifier
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needrain
Sep 21, 2016 8:55 PM CST
Thanks Maryl. I know all about erratic winter weather - and erratic weather in the rest of the seasons too nodding . I had not heard that going dormant in the summer affected rust. I was just wondering because I haven't seen it here. I just had a few that I allowed to go deeply into that dormancy and a few had no green left. When I cleaned the foliage off and started keeping them moist, they grew quite well. To all appearances they went just as dormant as those that disappear in the winter months. I keep watching for rust because I think it should manage to survive here, but so far every time I've thought it might be showing up nothing has materialized. I think your normally hot, windy summer conditions with low humidity probably match my conditions better than most people. If rust survived weeks of triple digits in your location, then I've probably just been lucky. Thanks again.
Donald
Name: Maryl
Oklahoma (Zone 7a)
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Maryl
Sep 21, 2016 11:49 PM CST
Donald said: "I think your normally hot, windy summer conditions with low humidity probably match my conditions".
Everything you said was true except the low humidity. We have the worst kind of summer heat - hot and humid. For example yesterday the high was 99, but because of our humidity the heat index was 110. They had heat advisories out all over the place. It was even hard to breath. But will go along with you on the wind and heat. That's bad enough. Bless both our little hearts Rolling my eyes. ......Maryl
Name: Suzanne/Sue
Sebastopol, CA (Zone 9a)
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Calif_Sue
Sep 22, 2016 9:21 AM CST

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I believe it was Pat Stamile that once told our daylily club (or I read it on the Daylily Robin, my memory sucks) that if a vendor sprays regularly for rust, it never quite kills it, just keeps it at bay. Once a plant leaves their garden and that regular program is not continued, the rust can rear up in favorable conditions.
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Name: Larry
Enterprise, Al. 36330 (Zone 8b)
Region: Alabama Composter Garden Photography Garden Ideas: Master Level Plant Identifier Celebrating Gardening: 2015
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Seedfork
Sep 22, 2016 10:54 AM CST
I think Donald is asking if all the foliage dies back(the plant completely disappears due to summer dormancy) would that rid the plant of rust just like winter dormancy would up north?
I personally think that it would, but the difference being up north during harsh winters I would think all the plants would die back and thus not leave any rust in the garden to reinfect the other plants. But with summer dormancy only a few of the plants would die completely back, so there would still be plenty of other rusty plants to reinfect the ones that lost all of their foliage.
By cutting back the foliage to within an inch of the crown, I am planning on creating sort of "fake dormancy" in an effort to control rust. I don't have any illusions of actually getting rid of it all together, just reducing the spread of it during peak blooming season.
Name: Karen
Southeast PA (Zone 6b)
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kousa
Sep 22, 2016 10:57 AM CST
I found a small amount of rust on Incandescent daylily so I stripped off all the green foliage and cut off most of the top except for the 2" of white growth and then sprayed fungicide on it. In fact just to be safe, I did the same on all the plants in my order and sprayed fungicide on all of them for prevention eventhough none of the other plants showed rust. These stripped off foliage was immediately placed in a bag and disposed in the trash. Some of my plants ordered in the spring from Floyd Cove had rust when I pulled off the foliage. I did the same as above and sprayed the plants twice a week the first week and then once a week after for the month. To this date, I have not seen any rust in any of the Floyd Cove plants. It is important that you check the plants before you plant to see if there is any rust hidden in the foliage. You will see the orange spores hidden in the foliage when you strip them down to the white part.
Name: Donald
Eastland county, Texas (Zone 8a)
Region: Texas Enjoys or suffers hot summers Raises cows Plant Identifier
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needrain
Sep 22, 2016 1:13 PM CST
Larry is partly correct here: "I think Donald is asking if all the foliage dies back(the plant completely disappears due to summer dormancy) would that rid the plant of rust just like winter dormancy would up north?". When the foliage is all dead, how would it live?

But the other thing is that, so far as I can tell, it hasn't shown up at all. Every time I've noticed rusty looking discoloration, a close examination doesn't fit what I perceive as descriptions of rust. Even more, those discolorations don't progress. I'm familiar with leaf spot on iris and, given the right conditions it can progress rampantly and then disappear until conditions it likes show up again. Conditions affect how bad it is. That has made me wonder if something about my weather in the summer is suppressing rust. Since I purchase from areas where it should be happily thriving, the suppliers have either done an excellent job of eliminating it or there is something about my conditions that have so far inhibited it. It can't be temperature. I think some winter spells might be cold enough and of long enough duration to deal it a blow, but that would be unreliable. Certainly not last winter. Weather here is erratic, but heat is a given in summer. Often that is a dry heat with low humidity. I have wondered if rust requires a certain amount of humidity to thrive. It would get it here, but very erratically and normally only for a very short duration.
Donald
Name: Maryl
Oklahoma (Zone 7a)
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Maryl
Sep 22, 2016 2:13 PM CST
I think your lack of humidity Donald would be a plus in the spread of disease. I know that I couldn't figure out how, once I had stripped off all the visibly infected foliage, how the rust still kept spreading in our very hot, dry summer weather. Then I noticed the heavy dew in the AM. Water, even from dew, can spread the rust. Since I grow in pots, I took the ones that had had minor rust and were stripped of any rusty leaves , and put them under the porch where no outside moisture could reach them. The majority of them then remained clean underneath the roof...... Then too there were those daylilies that were smack dab in amongst the rusters and never got so much as a spot on them the whole season. Yesterday Memories was surrounded by rust and remained clean. Kansas Kitten, as another example, remained spot free until late September when it all of a sudden turned very rusty (and was pitched).......BTW, I only have one daylily that goes summer dormant to the extent that all the leaves are gone. Maybe for you that and the lack of humidity does play a part in keeping the rust at bay. Add to that a modicum of rust resistant daylilies and you could be relatively rust free. Lucky Dog-lol.......Maryl
Name: Sharon Rose
Grapevine, TX (Zone 8a)
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Altheabyanothername
Sep 22, 2016 2:18 PM CST
Donald-- I have dealt with rust twice on two new daylilies. Once I used a systemic and baking soda. Twice I noticed rust on Dusty Miller's. Here they never die, I end up with wood trunks on them. That year it seemed like it was going to spread throughout the daylilies. Now I will not keep a Dusty Miller or susceptible plants for more than 15 months. I wash all my daylilies with baking soda and dish soap in the spring. I am blessed that I do not have rust. I think it is the baking soda, but I have a lot of heat dormancy. Heat causes rust to go domant, but there has to be a point that kills it. I thought rust was not prevalent here because of the hot summers. The only part of the country that is continually hotter is Phoenix Az area. May everyone's garden experience blessings!
Name: Annie
Waynesboro, PA (Zone 6a)
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LysmachiaMoon
Sep 22, 2016 2:25 PM CST
As a gardener in PA, where we've been known to have very very cold winters (well below zero F), I can state positively that the cold winter weather DOES NOT KILL daylily rust, even though the plants disappear completely. The only control (not cure) that I have found is to cut the plants right to the ground at the end of their flowering season and remove every bit of the foliage (don't compost it...bag it for the trash). The new growth that comes up will be clean but there's no guarantee it wont come back becuase I believe the spores will persist in both the soil and any dead/cut foliage that was not removed.
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Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
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sooby
Sep 22, 2016 4:18 PM CST
Annie, the spores do not persist in the soil or in/on dead foliage for the duration of a winter where all the foliage dies back. The only spores that persist through the winter are the teliospores (winter spores) but they cannot re-infect daylilies, only patrinia. Usually in your zone the reason rust re-appears the following year is from new plants, or plants kept in a greenhouse over winter. It could theoretically also survive under a winter mulch that keeps the leaf bases green.

Sharon, I'm not sure if you were thinking dusty miller could pass rust to daylilies, probably you were not because it doesn't Smiling
Name: Maryl
Oklahoma (Zone 7a)
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Region: Oklahoma Enjoys or suffers hot summers
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Maryl
Sep 22, 2016 6:49 PM CST
Sharon: Ditto on what Sue said. There are different types of rust and they are host specific. Rose Rust will not infect Daylilies for instance, and Daylily rust won't infect roses. They are two different types of rust..... Until the discovery of daylily rust in 2000, there wasn't even an official name for the disease. Since then, Puccinia Hemerocallidis (botanical name for daylily rust ) has only been linked definitively with Patrina as an alternate host plant. At one point they thought it might affect Hostas, but that turned out not to be true. The only other plant I've read about as being possibly susceptible to daylily rust is Alceas (Hollyhocks) and that's still debateable. As for your Dusty Miller, I can find no reference to any type of rust on that plant. It is susceptible to Alternaria leaf spot which can look like rust when the lesions turn rusty colored, but it's not the rust disease that is on daylilies. Glad you found something that works for you though on whatever you have............Maryl
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
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sooby
Sep 22, 2016 8:37 PM CST
Hollyhocks have their own rust, which has been in North America a lot longer than daylily rust. I think the only connection with daylily rust would be that they are both in the Puccinia genus of rusts, Puccinia hemerocallidis versus Puccinia malvacearum. Hollyhock rust is different from daylily rust also in that it completes its life cycle on the one plant whereas for daylily rust to complete the full life cycle takes two.
Name: Sharon Rose
Grapevine, TX (Zone 8a)
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Altheabyanothername
Sep 22, 2016 9:24 PM CST
Dusty Miller does rust. Gardening Channel "how to grow Dusty Miller" lists rust on Dusty Miller. I have experienced rust on them first hand. When conditions are ripe for rust alot of plants can develop rust. Maybe each has their own type of rust, but that just means the conditions are favorable to rust. For me any sign of any kind of rust means to start washing. Daylily rust exists in Siberia and it is unknown how. I think the hot dry heat here plays a role to keep rust at bay. Another factor that I think that helps here are the continual high and low temperature fluctuations. The temperatures do not stay very long in the danger zone of 59F to 86F needed for rust formation. I am glad that I have something that does work for me. I hope that everyone can find something that works for them. Many blessings for everyone to have a healthy garden!
Name: bron
NSW-Qld border Australia
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bron
Sep 22, 2016 10:52 PM CST
Like Larry, I try to contain and minimise the rust I have. After trying to cook it by putting pots in full sun in our torrid summers, I nearly killed the plants and had plenty of rust. As Maurice has pointed out, the evidence is that strong heat stresses daylilies and does not kill rust.

After Sooby Sue kindly clarified to me that daylily rust is not systemic in the plant but is only in the green parts, I started to remove leaves as soon as there were signs of spores. I cut off half the long leaves to not shake the spores. Then I wipe hands on grass far away and return and pull the lower bits away. I try and do it before and after rain. Sue has said that a leaf must be wet for at least 4 hours for a spore to infect. They used to look great after rain for a week until spores broke out like crazy.

Where I have a strong plant that is covered in rust I remove all green parts (ragp) and cut the plant across fairly close to the crown. Often I replant these in a place where there is no rust. That has worked well so far even tho we have frequent showers, humidity or wind. Our low temps are very mild. Last night here was around 40 degrees, which is great for early Spring as we've already had nights with lows of 60 and humidity and peasoup fog.

I do not spray as I probably wouldn't get it all. If some plants become impossible I will bin them. I can't stand the look or feel of it. But when it last flowered my SPACECOAST RUFFLES even had spores on the scape, but I persevered and ragp without moving it, and it still look clean.

Unfortunately the first daylilies I ordered included some rated SS 5.0. They had no rust for a year until I got plants from 2 sellers claiming they had no rust. Some like DOUBLE PINK TREASURE, CLASSIC ROMANCE, HOT WIRE had spores when they arrived. Even APPLE TART developed spores so maybe it isn't AT. But better growing conditions often helps. Some that were terrible are now OK. Even MILDRED MITCHELL!!!

A big healthy leaf on a beautiful purple gladiolus developed similar looking orange spores. I cut it off at the corm, but it regrew well, complete with rust. I recalled a home remedy of milk for downy mildew on rockmelon/canteloupe leaves. So I throw diluted sour milk, cream or yoghurt over it and it sure kills the rust. Leaf looks bad too but better to my eyes. Hard to fget it oll over and would block a sprayer. Might pot the up so I can dip them. Glads in other parts of the garden are free of it, for now. Will try the sour milk product with frangipanis b4 they get big.
Name: Maryl
Oklahoma (Zone 7a)
Cat Lover Roses Daylilies Container Gardener Plant Lover: Loves 'em all! Cactus and Succulents
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Maryl
Sep 22, 2016 11:30 PM CST
Sue: You are probably right about the Alcea having it's own rust designation. I only mentioned it because of a link I had from Michigan State University that listed Alcea as susceptible (link below). I don't know how old the data was, so like the Hosta information it must have changed as time went by and new data became available. Science does keep advancing......Sharon: I don't get the Gardening Channel, so didn't know they had listed Rust as a disease on Dusty Miller. I just did a cursory run through for you about Dusty Miller's rust carrying over to Daylilies and couldn't come up with anything about rust on Dusty Millers. New information perhaps. As I said, I'm glad you have the situation in hand.........Maryl

http://www.pestid.msu.edu/plant-diseases/daylily-rust-puccin...
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
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sooby
Sep 23, 2016 5:16 AM CST
Maryl, thanks for the link. Pretty sure that's an error. I will ask them.

"Daylily rust exists in Siberia and it is unknown how."

Sharon, it is known how. It is because Patrinia grows there. That's why people here in North America are concerned about patrinia. The winter spores (teliospores) that can survive the winter on dead daylily leaves produce another spore type in spring that infects patrinia if it's around (they can't infect daylilies). The rust then reproduces on the patrinia and releases another type of spore that can affect daylilies again. See:

http://web.ncf.ca/ah748/Patriniaanim.html

If daylily rust could survive in Siberia without an alternate host, we would have daylily rust all over North America. Because some daylily leaves stay green in milder winter areas the rust can keep cycling in just the daylily spore stage without patrinia. Where the foliage all dies back it needs patrinia or it doesn't survive the winter. The cut off for the most part appears to be Zone 7 where it may or may not survive a winter depending on the severity of the winter.

Regarding hot weather, daylily rust spore germination is temperature and light sensitive as well as needing moisture. Once the spore has germinated and infected the plant internally it is not as bothered by the environment. For more info on this see the second question and answer on this page:

http://web.ncf.ca/ah748/FAQ.html

Edited for formatting issue
[Last edited by sooby - Sep 23, 2016 5:17 AM (+)]
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Name: Donald
Eastland county, Texas (Zone 8a)
Region: Texas Enjoys or suffers hot summers Raises cows Plant Identifier
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needrain
Sep 23, 2016 6:39 AM CST
Thanks for that link @sooby
Sounds like my natural growing conditions may combine several inhibiting factors much of the time. Those conditions can be erratic, though. Certainly the early growing season this year should have been conducive to an outbreak of rust. Temperatures in the right range and lots and lots of regular rain keeping foliage wet followed up a really mild winter. My daylilies looked great during that period. They didn't start looking sad until the temperatures got hot and the rain ceased. We've had a lot of unusually high humidity this year, but the heat and winds start up early in the day so I expect the foliage dried off. Reading the article makes me think my climate will normally be unfriendly to rust. Unfortunately it can also be unfriendly to a growing plant.
Donald
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
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sooby
Sep 23, 2016 1:15 PM CST
I tip my hat to you. Environment is everything for fungal diseases of plants, so there are other additional factors that can also come into play. For example the levels of nitrogen and potassium (and possibly other nutrients), the type of irrigation and the time of day it is applied, how far apart the plants are spaced, location in the garden and so on.

@Maryl, I heard back and it is confirmed that Alcea as a host is an error and it will be fixed. Lucky that you spotted and mentioned it!

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