Ailing Rhodo and Laurel - Doctor Needed!!!

Please help with my ailing shrubs. One Rhodo and a Laurel that are within 10' of each other have black spots, curled ,yellowing or brown leaves and leaf drop. Both are blooming beautifully. I've cut away browning stems. Another Kalmia died altogether. There are no large trees in this bed, only flowering evergreeen shrubs and low growing conifers. Thanks, Mary

A photo would be helpful, including a close up of the leaves. Did you look at the roots of the dead Kalmia for a root rot?

This message was edited Jun 9, 2008 9:08 PM

snapple, yes the Kalmia had root rot. I have to learn how to put photos on here. The new Rhodo leaves are emerging yellow and then staying yellow with green veining. They curl under and get dark spots and fall. The Rhodo doesn't really have stem damage

The Laurel leaves curl up , turn brown and fall off. The buds turn brown & fall off. There were darkened stems which I removed. The other 2/3rds of this plant is gorgeous with beautiful blooms and healthy new growth. Thanks, Mary

Oh my, there is a lot going on here. On the Laurel, under the bark were there any brown streaks? I don't want to let you think I have this figured out. Just trying to gather as much information as I can.

Thanks, I'm not sure. I'll look tomorrow. The soil is not the same in the bed where the Laurel died. Too rich I think. I had to raise the enbankment and had access to truckloads of humus. I think I overdid it. I did add lots of sand and peat in the planting. The surviving, but ailing laurel and Rhodo are in clay, amended with the peat, sand and humus

.They are 2' from the house. The both were put in 2 1/2 years ago and were beautiful until now. They are partially under an overhang from the house. There are brooms and azaleas and low conifers. in front of them. In summer, they get sun from about 4pm on. I water them and feed them with food for acid lovers.

Well, sand + clay = cement! But if you added large amounts of humus and peat that would offset some of the problems of adding sand to clay. There are a lot of things that could be causing the problems. To better sort this out ( I love a challenge plus I love rhodys) try to list each plant with its specific individual symtpoms and soil conditions and photos. For certain there is more than one culprit at work.

O.K. Snapple, you've motivated me. I plugged the camera battery in to charge!!! Now I have to figure out how to put the photo on here! LOL! Nothing like stretching the brain. I doubt that there is more than an ounce of sand in the mix. Maybe I should stop using it alltogether. I love Rhodos too, but I am enchanted by Kalmias. I've been reading about checking the soil PH, maybe I should buy a meter. Thanks, Mary

If the sand is that small a % it's not a problem, especially in light of the added peat and humus. Meter's are not that reliable. Don't waste your money. If you really want to understand your soil contact your local extension agent to see about submitting a soil sample for analysis. You local extension agent will most likely be the best resource to help sort out the problems you're having too. Unless it's plainly obvious from the coming photos that's where you might consider going for help. The link below is for soil testing information.

http://www.aasl.psu.edu/SSFT.HTM

This link is for your county office.

http://montgomery.extension.psu.edu/

The Cooperative Extension service has folk and resources specifically for providing gardening information and problem solving for homeowners and they love doing it. They will provide bulletins or fact sheets at no charge. If you are still stumped you can take in a branch(es) for evaluation and if they are stumped they will send them to Penn State for further anaylsis. You can't get better information anywhere.

Sorry Snaple, Been busy cleaning up storm damage! Rhodo shots!

Rhodo leaf

Dried up bud rhodo

Rhodo rotting branches

Healthy part of Laurel with new growth

Dying part of Laurel

Go figure!

Close up of dead Laurel leaves

Hopefully someone else will have some insights into the browning leaves, but the "healthy" leaves on both your rhodie and the laurel look very chlorotic. Do you know what your soil pH is? Both of them prefer acidic soil and if your soil is alkaline that can make it so the iron in the soil isn't available to the plant which will make the leaves look like that. Either that or if your soil is already acidic then they need some iron. I'm not sure if a pH issue with your soil could cause the browning/dying, I think that's more likely to be a fungal issue, but if the plant is stressed from not having the right nutrients that could make it more susceptible to fungal infections.

Snapple, Thanks for the links. I am going to send them some soil samples. I do feed them with acid food. Did you see the weird mushroom in the first shot!!!!

Thank you, ecrane. In what forms do they sell iron? Should I stick a piece of metal in the ground?

I'd check your pH first, you might have plenty of iron there but if your pH is high then the plant can't take it up and adding more won't help. Most of the acid plant fertilizers have iron in them and since you said you've been using those I suspect your pH is off (sometimes when you have acid lovers planted in foundation beds it can be problematic because concrete in the foundation leaches a little bit of lime into the soil and raises the pH).

But I really think you've got some sort of fungal thing going on there too, and that should be your first priority since it's more likely to kill your plants. I'm not familiar with the various fungal diseases that these are susceptible too, hopefully snapple can help out with that. Since you already had a Kalmia there that died of some sort of root rot, it's possible that there's a fungus in your soil that tends to infect plants in that family in which case you may be best off finding a new spot in your yard and buying some new plants. Most of that sort of fungal infections are not extremely treatable so you may not be able to save the plants once they're infected, and once the fungus is present in the soil in a particular area you need to avoid planting susceptible plants in that spot again or else they'll get it too. I would check on your watering though--I had a tree that died from a soilborne fungus once, and what I learned with that one was that even if the fungus is there in the soil, it often won't cause problems unless you also are keeping the area a little too wet, then that gives the fungus and opportunity to move in and infect the plant.

Thank you ecrane. I'll ease off on the watering.This organic chemistry has so many variables. They were so healthy last year. I put them in 3 summers ago.

You don't necessarily have to ease off on watering, it's just something I would recommend checking since being a little too wet can increase your chances of fungal problems. But it's possible to get problems like this even if you're watering properly so I'd definitely check before you change things, no sense in stressing them further by not watering them enough if you are currently watering them properly. If it's a fungus like the ones that affected my tree, cutting back on water won't save the plants that already have symptoms, but if you have ones without symptoms and the area has been too wet, cutting back on the water might help prevent the healthy plants from getting the fungus too.

Thanks, ecrane. There are 2 Thugas and a Mahonia also in this same line up against the house. Would they also be subect to this fungus? Would they be showing signs of fungal disease? They were all planted at the same time.

To know if the Thuja and Mahonia are susceptible we'd have to know what fungus it is. They're not in the same family as Kalmia and Rhododendron which definitely gives you a better chance, but many of these fungi have a couple families that they will infect so it's not a guarantee that they wouldn't be susceptible. If nobody here has any ideas for you, I'd take some samples of infected leaves to your local extension office and see if they know what it is.

Did or do any of the affected plants have brown streaks under the bark of dying brances? If so the culprit is a fungus, Botryosphaeria dothidea. It isn't a soil born fungus. There are some sprays that can help and all the affected parts have to be pruned out and the pruning shears disinfected between cuts. The initial symptoms are dieback of selected branches. This is my #1 suspect for the
Rhododendron problem.

The other fungus likely at work here is Phytophthora which causes a root and crown rot. The initial symptom is wilting of the overall plant. This is of course a soil born fungus. There is no cure or control. Excessive wetness will encurage it. The only reliable weapon is prevention to make sure the soil is well drained.

The above are diseases common to both Rhododendrons and Kalmia. Kalmia can also get other branch or root fungus problems, with very similar symptoms. It's hard to sort them all out and see if they match what you have from photos. The link gives better descriptions of the symptoms than I can. Try reading the article and see if you can sort it out.

http://www.ct.gov/caes/cwp/view.asp?a=2823&q=377824

I hope you take ercane3's suggestion to get a soil test. It would be a very important step in getting the knowledge you need to get your gardens back to health and prevent future problems.


This message was edited Jun 12, 2008 3:42 PM

Thank you ecrane & Snapple, I am definately going to drop off soil samples this weekend. We had a tornado on Tuesday and there were days of cleanup and staking and replanting. I had a 20' smoke bush fall onto a young crepe myrtle and a 30' maple ended up inside of my apple tree. Had to be sawed out!!!

I will slice the bark tomorrow and look for streaks.

This is the only bed where I used Landscaping fabric. Could this contribute to the problem? It certainly makes it harder to feel the soil for dampness. Do you think that weird mushroom in photo #3 indicates fungal infection?

Snapple, thanks for urging me to master photo posting. I feel so empowered!!! Mary

As to the mushroom - they often appear on the surface of damp or wet wood mulch even when the underlying soil is sandy and free draining. It doesn't necessarily mean that the problem is drainage. Landscaping fabric shouldn't cause a problem either. I personally don't use it because It prevents the organic breakdown of compost into the soil and I apply compost on at least an every other year cycle. I'm always trying to improve the organic content of the soil.

That tornado thing. Ugly! Sorry that you had landscape damage but glad that's all you lost!

You will learn much from your soil test. While you are there find out what other diagnostic services they provide. Cooperative Extension is a teriffic program.

Hi everyone,

Pittsburgh butting in here.
I've also got a suffering Mountain Laurel. There are two trunks side-by-side. As you can see on the photo, one whole bush has wilted, turned brown & crispy, and is obviously a goner. I figured it was a fungus; last year noticed black spots on some leaves & sprayed with an antifungal soap. Also fed with a rhody food. This spring it looked fabulous, loaded with buds (hardly any last year) and I anxiously awaited it's blooming. But suddenly that one side stopped bud growth, and as the other side started blooming & putting forth vigorous new growth, the other side gave up the ghost.

Hubby blames the hose-end plant food sprayer I used. I blame the insane weather change we had here: from below normal (frost & all!) throughout May, to suddenly in the 90's & humid as all heck. My poor azaleas, which had just started to bloom when the heat hit, just wilted all their white flowers. :(

Another shot showing the spotted brown leaves, and green (fungus?) on the branches & trunk.

We're cutting out the goner this weekend. Any suggestions on helping the survivor? Would another antifungal soap spray or soil soaking help?

One last shot, of the beautiful flowers on the 'healthy' side of this Mt. Laurel.

stormyla, my heart goes out to you with the storm damage, as well as all those folks out in the Midwest.

Cheryl in Pittsburgh

Edited to add a P.S.: that mushroom in the first shot? I thought it looked like a gourd that had been tossed into the garden?

This message was edited Jun 13, 2008 9:50 AM

Whenever I've had something like that where half the shrub looks dead like that it's always been either a fungus, or there was some damage done way down low on that stem--something chewing on it, or somehow accidentally getting bent/broken to the point that water/nutrients can't travel up the stem anymore. The leaf spots do look fungal, but it's probably still worth getting down in there and taking a look at the trunk that goes up to the dead part and see if it's been chewed, bent, broken in any way.

I think that's leaf blight. It is a fungus - Phomposis kalmiae - which can be severe enough to cause twig blight. The treatment is removal of all infected plant parts and an appropriate spray. It used to be Benomyl, but I don't believe that is on the market any longer. You will have to read labels on the available fungicides for the correct spray. Clean up of all infected plant material is very improtant.

we have a problem here with rhodies,azelia ,and on one maple tree . i don't remember the name of it but will ask my dss tomorrow . it's a worm that starts down on the very bottom of stem,and eats the center out of it all the way up .the leaves on the tips wilt first ,then just kills that one stem and all the leaves look just like the pictures. cut the stem off as close to the ground as you can ,then look at the stem to see if it's hollow. if it is ,you can use systemic spray on plants to keep further damage away, but it's best to use it in early spring and again later in the year ,or as directed on label. it attacked my maple up on the trunk in a crouch ,it was about 4 " around and lost the tallest ,largest stem on tree .never could see where any of the worms entered . sally

There is a rhododendron borer that attacks by burrowing into the stem. It doesn't cause leaf spotting but it does cause leaf discoloration. The symptoms are wilting, discolored leaves and dieback. It is possible to have a fungus leaf spot and the rhododendron borer at the same time. It isn't really a worm but the larvae of clearwing flying insect. You can prune a wilting branch and locate the larva for identification. There are control treatments available. Here is what the University of TN says about Rhododendron borers. " Rhododendron is the preferred host of the rhododendron borer, Synanthedon rhododendri (Beutenmuller), while mountain-laurel and deciduous azalea are attacked occasionally. Spray the trunk and branches with chlorpyrifos or lindane in mid-May and June."

There are a couple of borers that attack maples, but they are not the same as the rhody borer.

thanks ,snapple. i have that cleared up . all i know is i don't want any more of them . last year it was a klondyke azalea that got hit ,again ! our extension agent recommended a name brand systemic spray and drench but don't know what the active ingredient was .does lindane have an offensive odor? the stuff i used sure did .went out to check it and container was gone ,dh must have disposed of it .need to pick up more. i was never brave enough to cut the wilting stem ,afraid i'd be wrong and ruin the shrub for nothing . course the stem would die anyway, the worm or grub would be long gone by then . sally

Neither one is exactly a perfume! LOL But yes, of the two chemicals mentioned, my nose says that Lindane is the winner in the stink department. Chlorpyrifos - trade name Dursban - is being pulled from the market. Lindane has recently been pulled also or is about to be. Both for toxicity.

I recommend Bayer Advanced Tree and Shrub.
http://www.bayeradvanced.com/product/Tree-Shrub-Insect-Control/super-concentrate.html

This is a new introduction, available at any garden center. It works systemically throughout the season.

This message was edited Jun 13, 2008 1:40 PM

that's for me ,thanks again, i don't know how you keep up with all of it . sally

Laurel stripped bark off branch

Rhodo stripped bark off of branch

Snapple, I read all of those links you sent. In the bed where the Laurel died of crown rot, i also lost 2 Azaleas. This bed has mice and moles. I've put down grub x and Moleaway several times.

We had a cool wet spring.

The mulch was damp when applied.

The bed in the photos has lots of spiders and grasshoppers. Thanks, Mary