HELP! Asters turning brown!

aunt_lou(Z5 OH)August 15, 2007

I have a long row of purple dome asters along the top of a native stone wall. Last year it was absolutely beautiful! Lately I have noticed that the stems underneath and bottom leaves were all turning brown but there were still lots of green bushy leaves at the top of the plant with buds forming. Now the tops of some of the plants are turning brown too! It started at the south end of the row and is creeping north and most of the plants are affected. I have been noticing webs now and then among the leaves but didn't think much about it---just knocked them off as I watered. Could it be something called spider mites or some other garden pest? Or maybe they got a whiff of weed killer? Other plants near by don't seem to be affected---yet anyways. Hmmmmm???? What do you think it is? What should I do? I hope someone has some advice for me. Thank you for any help you can give me.

Aunt Lou

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aachenelf z5 Mpls

My Purple Dome has done that too in past years, but I always assumed it was because I didn't water like I should have. This year I made a real special effort to keep it moist and I haven't noticed any browning yet.

If you do have a mite problem, your hose should take care of them if done regularly. Are the webs really tiny? Spider mite webs wouldn't be visible unless you really got close to the plant. They're not like regular, old, spider webs.


    Bookmark   August 15, 2007 at 5:30PM
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My purple dome has the brown dead stuff at the bottom of the plant too. I assume it dried out too much during our drought. The top is fine though.

I think you might have spider mites that are killing off the top growth. Spray the plant with water once a day for a couple of days in a row. Try to spray from the bottom of the plant upwards as they live under the leaves.

My Purple Dome tipped over during the rainstorm. Is there any easy way to fix it? I thought about trying to stake it but it's really big and it tipped backwards so any stake would have to go in front of it and be very visible.

    Bookmark   August 15, 2007 at 8:43PM
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tess_5b(z5b S.Ont.)

I lost two of my purple domes just recently - found them as brown crispy things last weekend, yet the other two that are maybe 6' away from the dead ones are perfectly fine, not a spot of brown on them at all. Weird. I will definitely be more vigilant about watering my remaining two.


    Bookmark   August 16, 2007 at 11:44AM
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athenainwi - I thought Purple Dome was supposed to stay short? You could try cutting a 1/2" diameter tree branch that has several forks and sticking it into the ground behind the aster to prop it up.

    Bookmark   August 17, 2007 at 11:43AM
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aunt_lou(Z5 OH)

The webs are big so don't think it is spider mites. Could be because of the drier summer than normal for here in Ohio and it was so hot the first week of August too. I don't water everyday but still 2 or 3 times a week but I have observed that my Alma Potchke asters up by the house that have a soaker hose under them are greeen and bushy from top to bottom so maybe the water thing is the key.

:-[ The Purple Domes at the south end of the row are dead already. Crispy brown from top to bottom. Bummer! Guess I need to get a soaker hose under the plants along the wall then.

My APs are so tall [4-5ft.] that some are leaning over and I need to get them staked up as well. I usually put a stake on each side of the plant and wrap twine around stakes and plant all. Worked well last year.

    Bookmark   August 17, 2007 at 12:49PM
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Well, Purple Dome does stay relatively short, but it does get to be quite bushy. Anyway, I ended up just pulling the whole plant forward so now it leans forward in the garden instead of backward. That seems to be working. If that doesn't stay then I'll try the tree branch idea Entling.

I'm sorry to hear you lost some Aunt_lou and Tess. I didn't realize they were that sensitive to drought. I'll have to keep mine watered better next year too so I don't get the brown bottoms.

    Bookmark   August 17, 2007 at 5:34PM
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dreamercp(Zone 4)

My asters are turning brown too. We've had 10" of rain in August so it can't be too dry. I decided to cut them back and the stems are green so I quit. I have two dwarfs and two Purple Dome that have turned brown. I'm going to spray them with something for blight and see if that helps. I have tons of asters of all kinds. The New England Asters are doing fine.

I always have to stake my tall asters because the wind knocks them over here and there. I have a dwarf that is 4' tall - all my asters grow big. I can't imagine if I fertilized them.

If anyone knows the real answer from crispy brown asters, please tell me. I don't want to lose any more.



    Bookmark   August 18, 2007 at 2:08PM
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aachenelf z5 Mpls

Well, well, well.... I took another look at mine today and they too have some crispy leaves near the bottom of the plant. Not too bad though. I guess it isn't a watering problem.

Found this also. From Johnson's Nursery:

"Asters are a third plant with great fall color for sunny locations. My personal favorite is Purple Dome (Aster novae-angliae 'Purple Dome'). The flowers are royal-purple with a yellow center and make a bold fall color statement rivaled by few other plants. Asters like to be kept evenly moist throughout the growing season. They may develop fungal problems that cause them to lose their lower leaves, but do not kill the plant. Thinning the plants in early spring can allow better air circulation and lessen the problem, and planting shorter perennials in front of them can hide the unsightly lower leaves. Here at Johnson's we have planted Clara Curtis mums in front of Purple Dome asters for a spectacular fall display! Cut plants down to ground level and mulch when the soil begins to freeze."

Looks like it's a fungus problem.


    Bookmark   August 18, 2007 at 4:03PM
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dreamercp(Zone 4)

I want to update about the asters that I cut back. I see tiny leaves starting to sprout, even on the ones that I didn't cut back. I also bought a three in one funguscide, insecticide and mitecide. That way, whatever the problem, I'm covered! I have even more asters that are turning brown. Every day, I find more. I keep cuttin them back and spraying them. I'm hoping they make it through this year even though I won't have flowers this fall.


    Bookmark   August 20, 2007 at 9:19PM
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aunt_lou(Z5 OH)

Thanks, Cheryl and Kevin. I too have re-thought this whole ordeal and it just can't be because of drought. As I said, I water at least 3 times a week and sometimes through June and July almost everyday. Also the fact that it is gradually spreading up the row is suspicious. Now whatever it is is attacking my dahlias! I too purchased a product that will supposedly kill mites, fungus, mildew, rust, etc. and plan on spraying it as soon as these rains we are currently getting let up. I am going to cut the most diseased plants down to the ground hoping that they will come back like Cheryl's. I won't have that glorious purple row this fall like last but hopefully the plants will survive to bloom next year. I've had Purple Domes for 5 years and never had anything like this happen before. They are one of my favorite perennials.

    Bookmark   August 21, 2007 at 12:47PM
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christinmk z5b eastern WA

My New York aster is doing the same thing! I actually noticed this unusual browning early last month, and asked about it here. Someone suggested it was just summer heat stress...but obviously not if everyone is having this trouble. What a bummer! At least im not alone in this. I guess its just not a good year for the aster.

    Bookmark   August 22, 2007 at 5:34PM
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Monique z6a CT(6a CT)

I'd like to know why Asters turn brown also. I've had multiple cultivars and most of the foliage turns brown starting from the bottom and sometimes it reaches where the flowers are so I pull them out. I've had the best luck with 'Alma Potschke' and 'Fanny'. I'm not into spraying, so bye bye Asters.

    Bookmark   August 23, 2007 at 12:35PM
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aftermidnight Zone7b B.C. Canada

I have a large Aster bed which is mulched with newspaper and maple shavings. I think the trick with Asters you have to keep the soil evenly moist at all times. There might be two or three in the bed that have a few yellow leaves at the bottom, that's not bad out of bed of 50 or so Asters. In another part of the garden in a holding bed, I have one or two Asters with quite a bit of brown, this area has been neglected as far as regular watering and is not mulched. I also find keeping the soil evenly moist keeps mildew at bay.


    Bookmark   August 23, 2007 at 12:57PM
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jean001(z8aPortland, OR)

Look very closely at the browned leaves. Among them you'll find small glossy brown pupal cases inside some of the rolled leaves.

The culprits are tiny caterpillars. You may still find some near where the brown leaves meet the still green growth. The adults are small moths, a scant 3/8 inch long.

The webbing is from the caterpillars.

At my place, these fellows have had lunch at my asters' expense for the past 5 years. The only remedy I've found effective is to spray Bt at the first sign of damage, making certain I contact all the lower leaves.

    Bookmark   August 23, 2007 at 2:17PM
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dreamercp(Zone 4)

Here's an update to the update - the asters that I cut back to 8" to 10" stems are starting to sprout leaves. I've been searching everywhere for the answer. I was sent a link to a site explaining "aster yellows". Hee's the site:

Here's a bit that I copied and pasted if you are interested: Asters have stiff yellow growth with many secondary shoots and are stunted. In warm weather, symptoms are more severe, and appear more quickly. At 55 degrees or less, plants may be infected without the symptoms being obvious.

Aster yellows is caused by a tiny organism known as a phytoplasma and is spread from plant to plant by leafhopper feeding. In Minnesota, Aster Yellows follow an outbreak of the 6 spotted, Aster Leafhopper. Although its eggs can survive Minnesota winters, most adults migrate or are blown here from the south in the spring. Adults are pale green, up to 1/8 inch long, and feed on the under-side of leaves. Touching a plant will cause them to hop or fly away quickly.

Once infected, there is no cure. Diseased plants should be promptly removed and discarded to reduce further spread. Control weeds, such as dandelions and plantain, which may harbor the pathogen. Plants and some varieties vary in resistance. Some research indicates that the use of oat straw mulch may reduce leafhopper numbers. Insecticides are generally not recommended for control of leafhoppers in the home garden.

I hope this helps. I'm still cutting back more asters. This has gone through my entire garden. New England Asters aren't affected and I have at least 50 so I'll still have some fall color in my gardens but I do have ugly all over too. I'm so upset.


    Bookmark   September 4, 2007 at 4:57PM
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The browning of the leaves is most likely powdery mildew. Asters are prone to this just like phlox, zinnias and many other plants are. Thinning them out may help, but with my phlox, it's just an ongoing thing every year. It just depends on the weather on how bad they get it. My asters, 'Professor Kippenburg' haven't gotten it yet. I've had them for 4 yrs. Stress can cause them to get it when not watering them enough or watering too much. Make sure they have good soil, fertilize, mulch and water deeply about once a week. Over watering can do as much harm as under watering. Of course if there's a lot of rain, we can't control that. Try not to water overhead, but just water the ground. I use a water wand. Good air circulation is a plus. But like I said, my phlox still get pm every year no matter what I do. They also come back every year full force. I've heard that a solution of a 50/50 nonfat milk/water solution will help keep pm at bay with the phlox, but I've never tried it.
Good luck to you all. Even though my asters don't get pm, my phlox still do so I know how you feel.


    Bookmark   September 5, 2007 at 5:49AM
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aunt_lou(Z5 OH)

wow! I would rather it be the powdery mildew than the aster yellows for sure! That sounds like wicked stuff there!

I would absolutely hate to dig up all of my Purple Domes and toss them so I am cutting them all back to the ground---going to spray them good with NEEM ---and hope for a better year next year. Next year I may thin them out considerable ---they are pretty close together---and I will try the tip on mulching them well and possibly putting soaker hoses under them to keep them more evenly moist and not water on the top. I also think I will pinch them back like I do mums---up until the 4th of July. Does anyone else do that? I read recently that they recommend pinching asters back just like the mums and I never knew that before. Maybe that will help also. Hope so.

    Bookmark   September 5, 2007 at 6:30PM
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ellen_s(z5 centralMA)

Lower leaves on asters turning brown is a common problem in dry happens to mine most years, but it still blooms fine for me, it just looks awful! But I don't spray or do anything and they still bloom like crazy...

    Bookmark   September 5, 2007 at 7:53PM
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Mine only get around 12" so I don't pinch them. They still aren't blooming yet, and pinching would make them bloom later and I don't want that. I think that would make them bushier and have more blooms, but mine get tons of flowers.


    Bookmark   September 6, 2007 at 5:12AM
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dreamercp(Zone 4)

I'm basing my aster yellows on one plant person's diagnosis. I have no idea if it is or not but I do know it isn't powdery mildew. I have that on other plants. Whatever is turning my aster's leaves crispy and brown like the color of chocolate is definitely not powdery mildew. I can't touch the leaves because they fall into a million little pieces like burnt newspaper. This isn't a few brownish green leaves on the bottom of the plants. My entire plants are completely chocolate brown with crispy fragile leaves. When you run your hand up a stem, all the leaves just crumble off. I've never seen anything like this.

The bad news is you can't get rid of it and it affects many other flowers like anemone, calendula, Centaurea, China aster, chrysanthemum, Clarkia, cockscomb, Coreopsis, cosmos, delphinium, daisies, Gaillardia, hydrangea, marigold, Nemesia, Paris daisy, periwinkle, petunia, phylox, Scabiosa, snapdragon, statice, strawflower, veronica, and zinnia. I hope whatever I have isn't aster yellows because I have two thirds of the flowers that can be affected. Some of my zinnias are already dead. I have some sick looking petunias. My millions of coneflowers look fine, so far anyway.

Oh well, I will cut everything back hard this fall and see what next spring and summer brings.


    Bookmark   September 6, 2007 at 3:04PM
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Cheryl, my phlox get those brown leaves too. When I grew the 'Profussion' zinias for several years, the bottom leaves always got it. Some of my phlox this year have almost the whole stalk either bare, because they fell off, or almost all bare with just brown leaves left. PM does that. Zinnias are known for getting pm. It starts at the bottom (where there is usually the least air circulation) and works its way up. It depends on several things on how bad it gets. There are all different kinds of pm too. My phlox have it, but my asters which are a short distance from them, don't. Different types of pm affect different plants. If you have a botanical garden near you, take a piece of your plant to them. They have master gardeners who know what to look for. Taking in a whole plant would be even better. I'm including a link about pm. If you look under symptoms, it'll say leaves can turn dry and brown. It can also disfigure a plant including the buds. I hope this will help put your mind at ease a little.


Here is a link that might be useful: Powdery Mildew

    Bookmark   September 7, 2007 at 5:36AM
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Loretta NJ Z6

I think aster yellows is more of a deformity than a die back problem.

    Bookmark   September 9, 2007 at 1:34AM
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I always get those crispy brown leaves on my purple dome asters. Annoying, but definitely not fatal and it really doesn't seem to affect the blooms, at least not for the past five or so years I've had them. Watering well seems to make no difference. I agree with the nursery that underplants them with other low growing plants to hide the lower stems; I use sweet alyssum myself. On the tiniest bright side, it does make it easier to strip the lower leaves for aster bouquets.

    Bookmark   September 9, 2007 at 10:33PM
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aunt_lou(Z5 OH)

This is not the usual crispy brown underneath stem and leaf. This consumes the WHOLE plant! They had tons of buds on them but this thing creeps all of the way into the upper foliage and kills it all! The whole plant is affected and the buds do not open as they too are yellow and brown crispy critters. No, this is not the usual brown stems that you plant something in front of and enjoy your fall show of blooms as usual. I have always had some of that ----no problem. This is a hundred times worse!


    Bookmark   September 10, 2007 at 10:38AM
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aachenelf z5 Mpls

Well, I'm still going by what I quoted above from Johnson's Nursery. It makes the most sense.

"They may develop fungal problems that cause them to lose their lower leaves, but do not kill the plant."

It would be interesting to see if treating with some kind of fungicide stopped the browning from spreading to the rest of the plant.

    Bookmark   September 10, 2007 at 10:55AM
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Aunt Lou, here's a clip from the link I left above:

"Severe powdery mildew infection will result in yellowed leaves, dried and brown leaves, and disfigured shoots and flowers. Although it usually is not a fatal disease, powdery mildew may hasten plant defoliation and fall dormancy, and the infected plant may become extremely unsightly."

My mums look horrible right now. It bloomed early, and looked fine. When I got back from vacation in early Aug. I could see it had pm. I cut many of the stems back because the buds were affected too.

Here's a description of aster yellows:
"The first symptom of the disease is vein clearing, the loss of chlorophyll or green pigment in the leaf veins. This is followed by yellowing of newly formed leaves, sporadic bushy growth, erect growing habit, and stunting. Stems and flower stalks may be numerous and spindly. Flowers often remain green and become distorted. Seeds and fruit do not develop. Specific symptoms vary with the kind of plant.

The leaves of infected carrots grow in tight bunches. The inner leaves are yellow and stunted, while outer leaves turn rusty red to reddish purple. The roots are bitter, stunted and deformed, with tiny hair-like roots growing all over the main root.

Infected glads may have thin, weak, yellow leaves, and the flower spikes may be twisted and deformed, while the flowers remain green. The whole plant is generally stunted and spindly, and the top is often killed.

Asters have stiff yellow growth with many secondary shoots and are stunted. In warm weather, symptoms are more severe, and appear more quickly. At 55 degrees or less, plants may be infected without the symptoms being obvious. "

Some years can be really bad for fungal problems, the weather and plant stress are 2 things that can make it worse. Like Loretta mentioned above, aster yellows deforms the whole plant, including the flowers.


    Bookmark   September 10, 2007 at 3:18PM
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aunt_lou(Z5 OH)

Well, it could very well be aster yellows from these descritions of that disease----or it could be a really bad case of the worst p. mildew that I have ever seen. Either way I'm not going to have my usual 50' display of royal purple this fall. :-[

Major bummer.

    Bookmark   September 10, 2007 at 4:16PM
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aunt_lou(Z5 OH)

Thought I would update this old post of mine for those who might be interested. I ended up cutting all of the purple domes down to the ground and spraying them really well with neem oil. After I cut them down, I saw that this disease had started to spread into the creeping phlox in front of the asters so had to drastically prune them too. Some beautiful silver wave petunias in the area were not affected at all and are still in full bloom. I do not think it was/is the aster yellows therefore. Also, as I dumped my wheelbarrow of aster branches onto the burn pile, I noticed the bottom of the wheelbarriow was full of some tiny---maybe eighth or quarter of an inch greyish brownish rectangular shaped bugs! Eeeeuuuwwww! So I don't know if it was these bugs or fungus.

My Alma Potschke asters up by the house had their usual brown legs but the top/main plant was gorgeous this year and absolutely covered with red violet blooms! They are only about 30 feet or so uphill from the purple domes----so--?????

Anyways, at first I was going to let the PDs go until next year but lately decided to take more drastic action. I am digging all of the ones along the top of that wall up and pitching them. I will keep a clump or 2 of PDs in another flower bed just cause I do love them. I am gradually replacing their long line with the new Double Knockout roses ---- spaced every 5 feet with purple/lavender or pink iris planted in between. I am hoping it will look as lovely as the way I see it in my head. lol

I wonder what some of the rest of you that added to this post ended up doing about your asters. Hope you all found a satisfactory solution for your aster problems too.


    Bookmark   October 23, 2007 at 12:49PM
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Well, I'm jumping in here very late, but my Asters' had this same thing. I think it is a mildew, I just removed all the brown leaves, and cut back on the watering. We have a sprinkler system. I did more hand watering, they still looked nice. Also, they need to be divided every two years, they start dying out in the middle, so you take the outer portions, and toss the centers. I only paid 1.00 for mine last fall, and boy was I pleasantly suprised, they're gorgeous.

    Bookmark   October 31, 2007 at 8:29AM
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The mum that had the pm so bad I had just moved to this area. It was stressed from the start. Then in July we got our hot dry weather. In early Aug. it was really bad. So I cut a lot of the really bad stems down. I still had some blooms on it though. I'm going to give it another year. If it gets bad again next summer, I'm going to get rid of it. I have several 'babies' from this one that I left in the old spot. They did just great and they get only about 4 hrs of sun. So I'll see what happens next summer and go from there. The transplanted mum that did so bad is by my asters and they didn't have a bad case of pm at all..just the lower leaves.
Aunt Lou, your plan sounds really good. I've heard Knockouts are a good carefree rose. Then only thing I'm not thrill about with them is they don't have a scent, but their flowers and disease resistance help make up for that.


    Bookmark   November 1, 2007 at 3:12AM
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aunt_lou(Z5 OH)

Ha! Yes! Wouldn't that be something----if only Knockouts were fragrant----on top of all of it's other wonderful attributes! Wow! Then it would be practically perfect!

    Bookmark   November 1, 2007 at 7:02AM
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