Any advice? My new yard has some beautiful plants that were neglected by the former owner. The dogwood is about 40 feet tall and the upper third looks pretty healthy. The lower branches and leaves are quite damaged by the disease although the trunk looks fine.
I've read about prevention (which I wish had been exercised here) and control, but I'm not sure if it's a lost cause. Anyone have experience combatting this disease? Should I spend a few years trying to revive this tree or should I begin thinking about what to put in its place?
Even if you choose to try fungicides to come to a stalemate with the fungus, the tree will always remain infected and the dead and diseased portions will not renew themselves. Injecting fungicide is expensive, and it only delays the inevitible. I would personally take it down now before it could infect any other dogwoods in the area (if that hasn't happened already) and replace it with something else. No sense wasting a couple of hundred bucks a year on something that can't be cured anyway, and if it's that tall, is probably already near the end of it's shorter lifespan anyway.
I agree with Sunflower. IME, only quite young trees are able to bounce back well from this problem and that requires both a diligent program of cultural control as well as regular spraying of fungicides. If the tree is heavily infected, it is only a matter of time before the disease takes its toll, regardless of how methodical you are about spraying - the fungicides are just not that effective and very difficult to apply thoroughly and with sufficient regularity on a tree of that size.
Other than selecting resistant species and hybrids for planting from the outset, I'd be interested to know what you learned about prevention - it is nearly impossible to *prevent* a fungal infection, but many can be controlled through management, depending on the problem. And there is a huge difference between prevention and control. FWIW, there are very few reputable nurseries in this area that even offer Cornus florida (or our native C. nuttalli) for sale any more other than a very limited number of more resistant cultivars as the disease is so prevelent and widespread.
I had a small one that seems to have recovered after I pruned off the diseased branches, but I suspect that it is just a matter of time before it gets re-infected. As others have indicated, a mature tree will be less likely to survive. I would plan on a replacement - perhaps a flowering crabapple. Also, I doubt that neglect on the previous owner's part played any role in the tree's demise. I don't why these trees are even being sold, but I see them every year. I have told people looking at them not to buy them, but obviously enough people buy them that merchants continue to stock the. The same goes with Bradford pears which grow beautifully for about 15 years and then break into splinters during a storm.
I am no fan of chemicals - by a LONG shot - but I respectfully disagree. It is most possible to bring declining flowering dogwoods around. The disease organism seems to be on the decline in many parts of the east in native woodlands. I am guessing that there may be a hyporvirulizing agent that attacks the fungus, as is often true of American chestnut blight.
I don't agree, I have a 100 yo dogwood in my front yard that deserves to be saved to the best of my ability. It is a lovely, lovely tree that would be missed by many people.... someone comments about it almost daily. This lovely tree was planted by the original owners of this house.
There is no cure or effective treatment for dogwood anthracnose. However, infected trees given ideal care are stronger at fighting off the cyclic attacks this disease makes on the trees, worse in years with heaviest rainfall. These are the efforts that will have some positive effect on the infected tree:
1) Careful watering during droughty months.
2) Perfect drainage during rainy seasons.
3) Mulching to limit its watering needs, starting one foot away from trunk extending to drip line or further.
4) Avoiding overhead watering & whatever else it takes to keep the leaves dry more often than wet.
5) Protection from bark impacts or injuries
6) Maximizing air circulation around the tree by having no other trees nearby.
7) Persistant removal & careful discarding of limbs & twigs showing signs of infection.
8) Persistant removal & careful discarding of fallen leaves.
9) Avoidance of fertilizers, or if used at all, lowest-nitrogen fertilizer once a year only, in spring. Sterile manure compost would be better.
10) Locate tree in sun. Despite that dogwoods like shade, alas so does the anthracnose, & the tree will adapt to too much sun more easily than to an aggressive flourishing of its chronic infection.
11) Religiously remove all brown leaves & discard carefully; diseased leaves frequently adhere to the tree year-round spreading the disease through to the twigs.
12) Never include dogwood leaves or twigs in the mulch.
13) Planting only low-water-use pernnials in the vicinity with the dogwood's needs exclusively in mind.
These methods adhered to strongly enough can mean a diseased tree will be attractive in more years than it will be unattractive. It will, however, still be a sick tree, & more prone to insect attack & other diseases.
A large tree, or a tree in the wild, will be impossible to assist to the fullest potential unless you really can crawl up into the highest branches on a regular basis to remove diseased leaves & trim diseased twigs & do everything else a high-mainteance sickly tree requires. Trees not rigorously cared for die within three years. With care, this can be extended to ten years. With a hardy hybrid, much longer.
Dogwoods may look very nice in alternating years; seeming improvement in a given year is invariably an illusion.
Non-organic chemical treatment with an array of fungicides have never proven to be particularly effective. Persistant use of fungicides occasionally helps keep the leaves from splotching so early in the year, without otherwise slowing the progression of the disease, & with the bad side-effect of lowering the fungal component of beneficial microorganisms thus hastening rather than retarding disease in the given tree. But in some years, properly timed use of fungicides will at least give the tree a better leaf look. Craig R. Hibben, a plant patholigist undertaking special studies of dogwoods & chestnuts, made a list of 8 points similar to mine above of what to do to lengthen the life of dogwoods. He left OFF the list the use of fungicides.
While some resistant hybrids are on the market, none of them are all that resistant, though better survivors with less maintenace if well positioned in a very sunny uncrowded setting.
The best hope for the eastern dogwood are the descendants of the surviving trees after mass die-off of dogwoods in Catoctin Mountain Park. These are the first & so far the only truly resistant C. florida stocks in production, but not yet widely available except to parks & forest areas where the species is being reintroduced after losing nearly their entire populations of dogwoods. Eventually the resistant strain will reach gardeners. Other resistant forests are being monitored in the northeast; it is beginning to not look hopeless for the eastern dogwood. Hope for the western dogwood is still not very good. However, after forest fires in British Columbia, the western dogwoods made an unexpected comeback that is not yet thought indicative of lasting improvements, but Nature may provide resistant wild trees for the western species given time.
When the disease progresses to blistering the trunk it is time for grief counselling & professional removal of every part of the tree that is above ground, including thorough cleanup of the sawdust scattered by the chainsaw. I would not at this time in history plant a native dogwood tree.
Feel free to disagree all you want - however, your experience with dogwoods springing back from this disease does not match mine. Or any number of local certified arborists, tree diagnosticians or forestry personnel. Perhaps it may be due to regional differences with this specific pathogen, however a mature eastern or native dogwood in this area infected with anthracnose is merely a casuality waiting to happen despite whatever treatment options one chooses to follows. Once contracted, the trees never recover, although the actual decline and death can be delayed with proper care. If you could in fact bring them back to health, I'd say your services would be very much in demand.
I see this is not such an easy decision! I appreciate the range of comments and that this group does not disintegrate into squabbling when they disagree. The reason I posted here was because I live in the Pacific Northwest and there are few people who have experience with this disease here. The tree in question is a Pacific Dogwood. It is tall enough and the damaged bits have worked their way high enough that it would be pretty impossible to prune them all. The crown looks fine as does the upper branches on the west side. If I get a cherry picker in here, I could cut away all the damage, but the tree would look pretty bare. I hate to just throw in the towel without even trying, but if I put a lot of effort into this with no result I'll be more attached to it than I am now. It's only been three months and I'm already having a tough time making the decision. Argh. There's just something great about buying a house with mature trees and shrubs surrounding it. That part of me wants to give this tree a chance. Again, thanks for the comments. I'll probably be back at some point with more new yard-owner questions. Best regards to you all, Samantha
Here, the large majority of C. florida in landscapes are sick, seemingly from a combination of anthracnose, alternating drought and overly wet conditions, and occasional salt spray and winds from hurricanes. I have never seen one come back, though I *have* seen a specimen or two in sheltered areas that have not succumbed. (Probably someone should clone one of them.) Also, when one drives away from the coast 30 to 40 miles, the proportion surviving is much greater.
To my amazement, people are still adding them to new beds or landscapes. They die.
I would like to believe that as Mike L. said, the disease may be diminishing, at least in some habitats. These are beautiful trees. However, the recovery is not yet in evidence here on the coast. We recently removed 8 specimens that were getting sicker after a few years of care (though not application of systemic fungicides). It probably doesn't help that there are plenty of sycamores nearby, all of which seem to carry some level of anthracnose or something similar.
Mike Prager Beaufort, NC (on the coast in zone 8a) (Remove spam traps from email address to reply.)
They have... I read an article that at the moment I can't put my hand on but there are disease resistant dogwoods out there, some cloned by a single tree in a field of very sick dogwoods. Colleen Zone 5 CT
As a fellow PNW'erner, the chances of your pulling this tree out of its slump are slim to nonexistant. Stands of our native dogwood are being decimated by this disease and it is near impossible to find one that is unaffected. I'd seriously review your replacement options - it is only going to get worse as time progresses.
I'm not sure I read your post correctly - did you say there are few people here in the PNW experienced with this disease? That is most certainly not true. Dogwood anthracnose (and Pacific madrone anthracnose) is a significant portion of the pests and disease curriculum of any hort course of study in this region and most qualified nursery personnel in the area are very familiar with the disease as are arborists, extensions offices and the forest service.
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