gardengal,
I too experience a similiar issue with an Ilex pedunculosa. Good growth through Summer, then chlorosis on newer growth late in the season. It eventually clears up and assumes the normal green coloration the following Spring. However, new growth again turns chlorotic late in the season on an annual basis.
I will await the responses of the smart folks.

Rx

There could be absolutely no relationship between the two cases. Some kind of analytical method, like sampling the soil (or better, sampling the foliage) needs to be employed to progress beyond guessing. Maybe there are even pathogens involved, if a serious effort is to be made to identify these tissue samples would be sent to a lab and placed on agar to see what grows off of them. Using this method distressed bigleaf maples at Seattle arboretum were determined to have several kinds infesting their roots.

Ron,
Your approach is sound, though not everyone has lab diagnosticians at their beckon call.
I was also not intimating that there was a relationship between the two scenarios. I dont even pretend to know much about Clerodendron, plus being on opposite coasts of the country makes it a ridiculous assumption. I was sort of venting, I guess, and waiting for a good suggestion.
I think these sorts of seemingly abiotic issues may be related to environmental issues such as sulfur dioxide or even stretches of high Summer temps - who knows.
I recently submitted foliage from a chlorotic Illicium on my property for foliar nutrient analysis. I also submitted soil from same plant for nutrient analysis and pH range.
It will be interesting to see the comparisons, but any disparities could be daunting, especially if there is a vascular issue involved.

Rx

A.L. Jacobson has showed me a book he bought at Flora & Fauna Books (Seattle) that is about nothing but non-pathogenic plant diseases. I think it's written in California, all or partly by University of California or California State University scientists.

It could be water-stress, too.

A photo would help us make the call. Can you post one?

Unfortunately, no, I do not have the ability to post photos. And I doubt it is pathogenic in nature as my garden is very heavily planted and no other plants are exhibiting these symptoms, even those in immediate proximity. The same with water stress, as the clerodendron is quite close to a grouping of stewartias and watering this dry summer has been diligent.

Late season new growth is very rich and green and looks perfectly normal. It is just the older foliage that is displaying the chlorosis and seems to be getting more distinct as the days go by. Very classic chlorosis - pale yellow leaves with deep green veination.

It IS pretty late in the season, but I am going to try some iron chelate and mulch with my usual fall topdressing of compost. We'll see if there is any change in this pattern next season.

All this is educated guesswork from afar; failure of your local knowledge base to provide answers is the greatest indication that you have issues difficult to solve. Any Clerodendrum-ophiles available in your neck of the woods?

I think Ron jumps the gun on these types of questions when he states "There could be absolutely no relationship between the two cases." There could be, but maybe he just can't think of one example.

I'll suggest one. Like Treedoc, I have absolutely no experience with Clerodendrum and wouldn't know one if it camped out on my front porch. I DO have experience with many different Ilex, however, and Treedoc's experience with his I. pedunculosa COULD be related to fruit production (if it is happening on a female plant). This is common; we see it around here in central KY most often on the commonly planted Foster hollies. As the Foster hollies go through fruit maturation on their copious clusters in the fall, the leaves turn conspicuously yellow on trees that don't receive additional nitrogen fertilization. This condition could be exacerbated by a less than ideal soil pH situation as well, where N uptake is impeded. Holly specialists' recommendation is N application to improve foliage and fruiting displays. You could attend the HSA national conference next month in Louisville KY, and verify.

Don't know, but this may be afflicting the Clerodendrum of GG out there in the Pacific South East (you might guess, rightly, that I've just returned from a visit to Alaska, where they claim they are more correctly the PNW of the USA). A soil test might confirm a low N availability, which MAY indicate need to supplement nitrogen while the Clerodendrum is in active fruit formation.

This diagnosis doesn't jive with the rich green new growth extensions, unless the extensions came first (Chicken? Egg?) and the fruit ripening followed. Or not. Or throw up your hands to the ALJ god.

Communicate any clarification of the Clerodendrum conundrum.

After considerable research and conferring with a few horticultural compatriots, I think my Clerodendron's problem may be one of manganese deficiency as opposed to lack of iron. Apparently my soil conditions are ripe for this situation - nearly neutral pH (6.5) and highly organic soil. This seems to result in low levels of manganese when combined with freely draining and well irrigated conditions. And high populations of soil organisms can also reduce the availability of manganese by oxidizing it to less available forms.

Most references stated that chlorosis resulting from Mn deficiency would appear on the newest foliage first, so that threw me off. Finally tracked down a more thorough review on the subject from the University of Guelph which indicated symptoms can and often do occur on older foliage as well. And that soil tests will only detect the presence of manganese but not its availability.

I have no idea how this might relate to Treedoc's hollies, but I figure it's worth pursuing for my clerodendron. Now the hunt is on for chelated manganese (which no one in these parts seems to have heard of) or manganese sulfate.

Interesting. I know in several different situations in my experience, we have found Manganese TOXICITY to cause similiar effects. One of the precursors to this extremely high (toxic) level of Manganese was annual, deep addition of hardwood mulch.
This was occurring on ericaceous material such as holly and rhodos.

Rx

Gardengal: Great sleuthing! Last encounter I had with manganese was as Water Treatment Plant Operator II (the other hat) for the thoroughbred horse farm where I was landscape manager. Potassium permanganate was one of the tools used in treating the well water around here. They finally wised up and connected to the city water supply. I remember a lot of purple days back then.

Here's another resource when the imponderable arises again.

Here is a link that might be useful: Gardengal could start her own show

This is the kind of thing I expected it would be, magnesium problems produce bright yellow foliage areas on laburnum; a friend is putting alot of a locally produced "manure" product on her plantings and getting bright yellow portions. I suspect the product is too alkaline for some of them, maybe contains mushroom compost. Also, application of inappropriate (alkaline?) fertilizer to rhododendrons at Rhododendron Species Botanical Garden one year resulted in bright yellow foliage. But without some kind of testing and analysis, it's all shots in the dark. Lookalike symptoms can have disparate causes, and different species can produce different reactions to same causal agent.

Rather than adding a chelate of magnesium, or even iron, a soil test (via a professional lab) would reveal if it's even needed.

Please reread my follow-up post - I believe the problem is a Manganese (not Magnesium) deficiency and a soil test will only determine the relative presence of Mn, not its availabilty. Apparently my soil conditions tend towards both low levels of Mn as well as unavailability of this element.

Anyone know what the pH of bagged, dehydrated cow manure is?
I am trying raise the pH in a bed of Illicium (see above) and I found out my pH value is 4.4 and want to raise the pH using something alakline. I have access to this bagged cow manure product, so wanted to find out the pH value.
I am open to suggestions as to proper amendment materials that will help get me heading to a pH of 5.5-6.5.

Rx

Sampling foliage is more to the point. Raising pH even one point represents an increase of many times, I would make applications of lime over a period of years. Meanwhile, if the shrubs are able to keep functioning maybe they don't really need it.

TreeDoc - I thought that I read somewhere that Illicium likes a somewhat acidic soil? Maybe I'm dreaming, as usual.

However, I have a contorted mulberry (I know, I'm not posting on the tree forum, but this topic brought to mind that I may have a manganese deficiency in my yard. I do use lots of cedar and other wood mulches. Some of the leaves on this absolutely gorgeous tree, turn yellow - solid yellow, some are mottled, and I wondered if I may have not only a manganese dificiency but a nitrogen deficiency as well. I could have my soil tested, but it's such a pain for me, as I work 5 days a week and just don't have time to do it.

Do the soil tests sold in garden centers really work?

Susan

Ron,

I am awaiting the results of the foliar nutrient analysis.
My plan is to remove a sizeable amount of the soil volume and replace it en toto with a mixture of the amendment and existing soil.
I am well aware of the difficulties altering pH, but these plants are stunted and chlorotic due to extremely acidic soil and low Ca and Mg levels.
So is dehydrated cow manure acidic or basic?

Rx

Because it has not gone through a composting process, it will tend to be basic - in some cases, extremely basic. And with high salt concentrations. I'd consider a pH test to determine exactly what you are dealing with.

Gardengal, Fertilome's Liquid Iron product contains not only chelated iron, but also chelated manganese, copper, and zinc. Is this product available in your area? It's widely available here in the Chicago area.

Gardengal, see above. I did sample my soil - my soil pH is 4.4.
P and K are very high and high, respectively.
Mg and Ca are medium and low, respectively.
Soil organic matter content is medium.
Nutrient retention capacity is very high.

Rx

Treedoc, I meant testing the pH of the dehydrated manure :-) Sources I have seen have listed it as high as 12.0, but depending on how it was dried (various heating processes typically, also to kill any pathogens), that could vary widely.

dwk001, Fertilome products do not seem to be available on the West coast. Safer also makes a chelated product, mostly iron, but has other trace elements including managnese. Unfortunately, the concentration at .75% is too low for my purposes. The article I read suggested 31% chelated manganese. Or manganese sulfate at 26-28%.

Posting this from England. The only Clerodendron trichotomum I have seen is so stunning that it made my head turn every time I passed. It is in a garden on the outskirts of Weymouth, a very sunny seaside town in the south of England. It was both the leaves and flowers that attracted me. The leaves were very pale in colour and made the small tree stand out. Eventually I stopped and asked what it was and ended up being given a sucker plant. This is growing well inland but the leaves have remained green so far. Checking the parent plant earlier in the season, that was fully green.
There is certainly no ill effect from the lightening leaves which presumably is what you are referring to. I would be pleased if mine followed suit, so if, as you say, you find it attractive, as I do, I really wouldn't worry.
My opinion, for what it's worth, is that it is caused by long hours of sunshine. Weymouth is the sunniest place in the UK.