I used to get quite a bit of SS each year until someone told me to spray the plants each Fall, just before the first freeze, with a systemic insecticide. That was to control Spring infestations of thrips and aphids. After I added that to my Fall regime, SS went down dramatically. Last Fall, due to health issues, I did not do my Fall insecticide spraying. This Spring was the worst for SS, aphids, and thrips in a Long Time. I will definitely spray this Fall!
I spray three times at five to six day intervals in early October. Our annual first freeze is Oct 14. If you want to know yours: https://www.almanac.com/garden...

Has anyone thought to do tests for plant virus on plants that have this problem?

Not that I recall, it doesn't really fit the pattern for a virus. The leaf streak fungus, Aureobasidium microstictum, has been isolated from several samples of spring sickness, and has reproduced something like it when injected into the plants. But the question then is how does it get into the plants naturally, which is why we think there is likely a pest involved.

Greg, what systemic did you use? Have you tried treating half the garden and not the other half and then counting affected fans in both?

Spring sickness can kill daylilies. We have to separate the effect of spring sickness on daylily clumps from its effect on daylily fans (individual daylily plants). Although it may affect a number of fans in a clump, depending on the number of fans in the clump it may not kill the clump. When we look at each individual fan it can and does kill some of the fans it affects.

Spring sickness may also prevent fans from flowering. Again, we have to separate its effect on clumps of fans versus its effect on each single fan (daylily plant). Depending on how severely a fan is affected, if it does not die, a fan can be so severely set back by spring sickness that it does not flower in the same year. If it is mildly affected by spring sickness and it recovers well it may still flower but we do not know whether in those cases it flowers as it would have if it had been unaffected by spring sickness - I expect that it does not flower as well as it would have. A clump with many fans may have some affected by spring sickness but the clump may still be able to flower well because of fans that were unaffected.

This year Little Showoff had two fans that were severely impacted by Spring Sickness. Both fans recovered somewhat. Both also sent up a scape that looked like it was coming up out of the soil. Both scapes were only about two inches tall. One scape had one bud and the other had two buds. A normal fan sent up a normal scape which is the normal height and has many buds.

I was shocked when those two little scapes appeared because I've never had fans look that bad and still manage to put up a scape.

I have a couple plants that always seem to get spring sickness every year. One is Daveo Holman. Hasn't bloomed very much as a consequence. It has not spread to the 3 plants next to it. Think I will try Greg's systemic insecticide in the fall. Any special one you use? I have Bayer rose & flower. Think It is a fert, insecticide, fungicide combo. Maybe the fertilizer part wouldn't be good that late in the season?

I was just outside and the normal scape of Little Showoff bloomed. Here are pictures of the short scapes and the normal one for comparison.


Way down in the foliage.



4-way branching.

Spring sickness at my place this year is the worst I have ever seen. A typical year I'll see a few daylilies struggling a bit with it, and some years quite a few, but this year more than ever. And with more pronounced effect than ever.



Some try to grow out of it but the new leaves aren't right. Often canoed, and/or stunted, and/or corrugated, and with curled/knobbed ends.


Some are putting out an abnormal number of new fans. These are 2nd year seedlings and while they are vigorous I have to wonder if the spring sickness is causing all the fans...




A lot of clumps are really stunted


Some look like they recover, and then new leaves start looking abnormal


This one recovering has a fused scape and the new leaves aren't right again


Seeing some of the classic serrated edge result but not very much

I'm concerned that the blooms will be affected and not be "true". Of course I'm also worried about some losing fans and dying...

If it's spring sickness and there are blooms the blooms may well be normal. It doesn't all look 100% like spring sickness but maybe that's because they're growing out of it so all the ugliness isn't showing as obviously. Have they had any previous pesticide/herbicide treatments?

My past experience is they grow out of it pretty quickly and everything is normal. This year they are not growing out of it very well at all. Highly abnormal looking. So I'm unsure of effect on blooms-- hopefully they will be normal
While I will on occasion spray, my recollection is that I did not spray at all last year. And certainly not yet this year...

@Dennis616, I'm glad you brought this post up. I've seen Spring sickness mentioned here and there on the forum but I didn't know much about it. Read through the thread and viewed the pics in the links and I think Spring Sickness is exactly what is going on with a few of my Daylilies. Here's some pics. Warning, not pretty. And as a side note, the things between some of the leaves are just stuff that has been falling everywhere from a tree, not bugs.


And here's the same daylily, different location. Looks like I may have cut out some of the ugly folliage but you can see, healthy growing fan next to the stunted mess.

These two are in pots. At first I thought the weather. We had some unually hot days back in early April and then it just got cold and dreary forever. Then I thought insect and treated with systemic pesticide. Then I thought drainage and drilled more holes in the pots. But then it didnt make sense that totally healthy growing fan(s) are growing next to the messed up fan. Had no idea until I read through this post and saw the pics in a link.

What's interesting to me at least, is the daylily that is pictured, I bought two of and split the clump so four plants, all in pots. Two are perfectly fine growing normally and the other two are as pictured. I have one or two other daylilies that may have had Spring Sickness too but seemed to have either grown out of it quicker or there are just more fans so its hidden more.

@Sooby, is there any updated info as to what causes this.

Passionate4gardening said:
@ Sooby, is there any updated info as to what causes this.

Not really. Bulb mites and the leaf streak fungus are still prime suspects that remain to be proven, but that doesn't exclude something else being involved. You can have an affected fan and a healthy fan even sharing crown tissue so that aspect is not unusual and still as much of a puzzle as ever! It has been shown that the damage starts while the buds/shoots are still underground after winter, just that you don't see them until the middle leaves have grown enough in spring to show.

for the information Sue.

I am not a scientist- far from it- but I can report what I see in my garden.

In 2022 I had no spring sickness at all- none! We were very cold well into April here, and the daylilies were slow to come up. When it did warm up, it stayed warm. This year we had very warm temps early which caused the daylilies to come up quickly, only to be hit with temps in the teens for quite a while after that.

For the last several years, I have been slowly weeding out my Tet plants that were affected with spring sickness. This year, there were only a few of them that got it, and those plants were more fully evergreen plants with the lighter green foliage. Those with darker green or blue- green foliage were fine.

I have only started seriously with Diploids in the last few years, but now have quite a few of them. There was a BIG number of Dips that got it severely. As with the tets, those plants tend to have the more evergreen plants with light foliage. I did notice that the worst ones had a crown at or very near the soil surface, and a plant in the same clump that was not affected came from a side shoot well under ground where the crown was not frozen. In some cases, I did lose the plants where the crown was exposed, but most did grow out of it eventually. I can also say that there were some new evergreen plants that were just added to the garden that I mulched with leaves and planted deeper in case the freeze/ thaw pushed them up, and those plants didn't show any signs of sickness at all. Only more evergreen plants with an exposed crown that had been frozen hard had any signs of sickness. Fully dormant plants and mulched plants didn't show any signs.

For the record, I have about an acre of daylilies, so it isn't just a casual observation, but that doesn't mean that it is a scientific study where results are absolute for every gardener.

@Deryll were the unaffected side shoots ones that were new that year, or did they exist the year before? From my observation it seems that fans affected by spring sickness are always ones that carried over from the previous year.

For ploidy and foliage habit I did an analysis one year and it turned out that 70% of my dips and 42% of my tets had spring sickness, and 61% of deciduous (dormant) daylilies, 46% of evergreens and 65% of SEvs. But it may depend on the selections of cultivars in an individual garden. Also that is based on registered foliage habit, which isn't necessarily how a cultivar behaves elsewhere than the hybridizer's garden. I remember someone else doing an analysis and finding no difference related to foliage habit. Also the same cultivar doesn't necessarily get spring sickness for everyone.

As mentioned above, the problem starts while the shoots are below ground, so it's not caused by weather conditions once the fans have started to grow above ground.

I have roughly 2500 clumps of tets, and we are talking up to 40 fans in a clump, and had maybe six that got spring sickness this year, while as I mentioned, there was none at all last year. The dips had roughly 50 out of about 400 or so. My results are nothing like yours though. The plants that seemed to get it had a crown at ground level to begin with. The side shoot fans were newer, but the crowns were beneath the surface, but are mature enough to bloom this year. It just seemed to me that what I call "spring sickness" was most likely the result of freeze damage, and while science grapples with the causes, I am going to stick with my theory if it means that I don't have much of it. There was a time when my tets did have a big problem though. I am going to try adding a layer of mulch this year to the diploids that are problematic to see if it helps. All I can do is try, right?


this photo shows just one of five "beds" taken two weeks ago, but I have deleted photos of plants with spring sickness already. This same bed is now double in size.

Deryll said: enough to bloom this year. It just seemed to me that what I call "spring sickness" was most likely the result of freeze damage,

Yes you are correct, spring sickness is not the same as freeze damage. They look quite different, but you can have both at the same time. Here's the ADS/AHS page for spring sickness, there are more pics and information at the link included on the page:

https://daylilies.org/daylily-...

To me, Spring Sickness looks a lot like snail damage. I've been growing daylilies for over 10 years and never noticed snails or Spring Sickness until last year, when both appeared on some daylilies at the same time. I didn't make the connection until this year when all of my daylillies are suddenly infested with literally thousands of snails. Before I started seeing snails, many of my daylilies were showing signs of Spring Sickness. Ever since I realized the snails were there, I've been picking them off in the evenings. While doing so, I've noticed that dozens of baby snails have appeared on the plants with Spring Sickness. I think the snails that survived the winter laid eggs in the daylilies when they were coming up in the spring, and the baby snails feeding down in the base of the new leaves cause them to be deformed. If a batch of snails hatches and feeds on buds when they start to come up, the flowers also seem to be deformed. If anyone is interested, I think I have amber snails. And they seem to love daylilies more than hostas, phlox and coneflowers. I hope I can enjoy some daylily blooms this year. If this had been my first year growing daylilies, I never would have fallen in love with them!