HUMMM what web are you using a??? type in google or yahoo Emperor 1 Japanese maple you will get a plethora of info. It is also called red Emperor or just Emperor they are all likely the same at least no one has given a plasible reason why they arn't... very similar to Bloodgood and several other bloodgood type selected seedlings ( I E Fireglow)...supposedly leafs out a bit ltr for northerners ... maybe by days...maybe a bit darker or brighter... You need to be a real acer lover to care about any differrnces IMHO If you asked a person going through your yoard and all three were next to one another they wouldn't be able to definitly say they are differnt although many of us wackos do see it as obvious ;>) David

This is my first post and keep up the good info!

My understanding is that the leaf of the 'Emporer' is smaller than the 'Bloodgood' and 'Bloodgood' is more susceptible to Vermercillium wilt. Any comments?

Neither idea is substantiated :-) Leaves are going to be very comparable in size, although 'Bloodgood' can produce somewhat larger leaves, but that is not a given. Emperor's leaves are thinner textured, so often more translucent in appearance. It is also reputed to hold its color better in full sun or in hot climates and leafs out slightly later than BG, therefore may be a better selection for more weather-extreme parts of the country.

As to susceptibility to verticillium wilt, ANY Japanese maple is susceptible and VW is an equal opportunity pathogen :-)

What is the group doing for prevention of delay of the onset of VM and once identified in a JM to delay the death of the tree?

I'm not sure I understand your question. Who is the "group"? There is a great deal of research and scientific study worldwide currently being conducted on the various strains of verticillium and developing plants that have resistance, however much of the focus is with more economically significant agricultural crops. How likely this type of research will be applied to more ornamental crops is a bit of a guess, but I'd surmise there is far less financing available to fund this type of study.

As to delaying the onset, much can be done by adhering to careful planting practices and scrupulous aftercare. Investigation is being conducted into various soil amendments that may contribute to neutralizing or slowing the emergence of the pathogen but nothing definitive has been concluded. Certainly developing a healthy, bioactive soil system should be helpful, as large populations of beneficial microorganisms can be a deterrent. Acknowledging the cultural requirements of the plants in question and reducing stressors that may reduce resistance and encourage the pathogen is extremely important, as stressed plants are far more likely to become infected than those in robust health. And understanding the pathogen and how it works can help as well.

Once the pathogen has infected the tree, there is very little one can do to stop the progress. Generally, once the disease becomes noticeable, it is typically too late to attempt much of anything, although pruning out affected branches/tissue is reputed to help. However, since the pathogen does not always follow a predetermined course once it has invaded the vascular system, pruning may or may not be effective. Older, established trees are sometimes able to compartmentalize the disease and restrict it to a specific section of the canopy - these subjects are more likely to respond to pruning. But one of the characteristics of this disease is often a very rapid decline, after which there is little, if anything, one can do other than remove the tree. It is not curable or reversable, so even more mature trees that have successfully compartmentalized the disease remain at risk of sudden death.

Mountain Maples in Potter Valley, California uses a product call Phyton 27 on all the Acer P. they propagate in their drip watering system on a preventative basis. Anyone else have any experience with this product?

Gardengal48,

Thanks for the info on verticillium wilt. I think that is what overtook my fisrt JM back in 2004. Does it strike the same area? Because I'm finding it hard to keep other JM's I've planted in the same area within a couple yards of where that one was healthy. Suddenly, in the past two weeks a perfectly healthy 'Osakazuki' I planted in Spring is inexplicably turning brown. I know it isn't due to under or over watering and not due to heat stress either--the temps have been in the lower 70's to lower 80's in the days and 60's at night.

The biggest thing is I started seeing the nice color of the branches begin to turn a uneven striped color. I already saw a small 'Bloodgood' I planted in the same area lose branches. First, loss of leaves and then the branches turning grey and dead. However, its a tiny plant now with tiny leaves still hanging on (literally 2-inches tall). I haven't seen the speckled or striped look, but I think this is because the 'Osakazuki' is a larger tree. I think if I wait the branches too will turn grey. I just pruned off these sickly looking branches with dropping leaves today to try and save what I can. It looks pitiful now but hopefully I can save the tree. Have you seen this pattern with verticillium wilt?

ezochi, it is typically suggested NOT to plant another Japanese maple (or other susceptible species) in the area where a previous maple succumbed to VW. The pathogen can stay active in the soil indefinitely and even the simple activities of planting and establishing a new maple in the same area can lead to sufficient stress to allow the disease to infect and progress. It's just not worth the risk. However, that doesn't mean you should avoid any more maples - just select a different location and provide the best care possible.

While it's possible the other trees do have VW, the symptoms and progress of the disease can vary considerably, especially with very young trees, so an accurate diagnosis is unlikely without analysis by a plant pathologist. Your local extension office can help you with this. If VW is widespread throughout your garden, growing JM's in containers may be the answer. After losing three trees to VW myself, all the rest of my Japanese maples and all new additions live permanently in a container setting :-)

Phyton 27 may be moderately effective in reducing the incidence of VW in a nursery growing environment, but it is not a practical application for homeowners. If it were that effective it would be far more widely available and promoted for that purpose.

Thanks for the info gardengal. I have other areas in the yard where they're doing fine so I'm not too concerned about other areas. I've just been avoiding that one area, near where that BG died a few years ago. I attributed it to my zone 5--exposure to wind--since I didn't have as many trees for protection like now.

I'm beginning to realize it may not be my zone at all. I began to suspect this after a second smaller BG as I mentioned succumbed to some kind of illness in the Spring--the only way to describe it. And now as I suspect a bigger tree. So it maybe that all along it was not lack of cold hardiness but rather VM wilt!!

I was avoiding that area but I began to run out of space for new trees so I started planting closer to there. I have a few I planted this Fall in the back of that area which is perhaps--hopefully!!-- far enough away, but I will observe them carefully.

I will monitor this 'Osakazuki' very closely. The plant has normal looking leaves now after removal of the wilted ones but I'll know in a week if the pruning worked or not. Because this illness I notice when it strikes moves pretty fast. The strange thing is though that when it struck my second BG as long as I pruned away the affected branches it lived. But that was already one of those "ebay sticks" so when I pruned it it is now almost nothing. But it's still alive and the tiny little crimson leaves are healthy so I can't get myself to pull it out.