Hi all,
All the dogwood trees in our area have leaves that are wilting and curling. The trees look downright sick. Is this how they would normally look this time of year?
I live in zone 5. Plenty of rain lately, so no lack of water.
-Chris Swartz
Hey, Chris! Do you live in the U.S.? My husband works for the Oregon Department of Forestry for our area, he says that our Dogwood trees in Zone 8 are doing great. He says he'd need to know where you live to be able to make a guess as to what's going on. I sure hope your Dogwoods feel better, if they are sick.
-- Bastet_HW Brightest blessings, Bastet
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Have you had hot weather? Curling under of the foliage with a limp appearance is SOP for dogwoods in hot weather, specially if they receive a good deal of sun. Just a climatic reaction, nothing to become concerned about.
pam - gardengal
"Chris S." wrote:
Yes, I do live in the states. Zone 5. I did spray mine with a fungicide because they had black spots and some leaves are turning purple and dropping. Temps have been in the 80's to 90's. I thought mine was the only tree until I started looking around. They all look like mine. My main concern was the health of the tree. It's mature and I sure would hate to lose it.
-Chris Swartz
Here in the northeast, dogwoods are subject to "dogwood decline", aka anthracnose, and this year it is particularly bad. Last year's severe drought stressed the trees, and this year's cool, wet, extended spring has allowed the disease to thrive. I have one dogwood that has been in decline for some years, losing twigs and leaves and such, that is losing entire branches this year. My "healthy" tree, that has resisted the problem so far, is showing signs of it this year.
It's a crying shame; they are such beautiful native trees, with a form and beauty unmatched by any other understory tree. But so it goes.....
Sue snipped-for-privacy@earthlink.net Zone 6, Southcentral PA
Ahhh....your first post omitted the spotting and discoloration. Sounds like dogwood anthracnose, a serious degenerative fungal disease. There is no cure for it, although keeping your tree in maximum health will prolong its life. The curling of the foliage is defintely a reaction to your temps, but that is not a manifestation of anthracnose - it will happen to perfectly healthy and disease-resistant dogwood cultivars in hot weather.
As to the health of dogwoods in zone 8, our native dogwood, Cornus nuttallii, also suffers severely from anthracnose and native stands are dying out. Ditto with most of the eastern flowering dogwoods planted in gardens here, Cornus florida. Surprised the forest service worker is not aware of this extremely common problem.
pam - gardengal
The same story is happening here in the Southeast, where the dogwood is virtually a signature tree. The problems are particularly bad near the coast, where they are stressed by periods of drought and (this year) unending rainfall; salt spray during hurricanes, and poor soil. What the anthracnose doesn't do, the borers see to.
We had to remove 8 dogwoods from our lot (that's all of them), and it was a disappointment. I see neighbors trying to nurse them into health, but they are not successful. Only an hour inland, the dogwoods are doing better -- for now, anyway.
Mike Prager Beaufort, NC (on the coast in zone 8a) (Remove symbols from email address to reply.)
A forest with 90 percent of its dogwoods dead by the end of the 1980s, due to anthracnose, was in 1990 found to have one tree barely afflicted, being highly resistant to the fungus, growing on Catoctin Mountain in Maryland. The tree was closely scrutinized & cuttings started from it by Professor Windham of the University of Tennessee. Read about Professor Windham here:
The university's horticultural extension and experimental station in Knoxville had the resistant dogwood under production & ready to release by
1998. The experimental station is also using "Appalachian Spring" to create other strains of resistant dogwoods, though no others are thus far released. Budwood is also being supplied to commercial nurseries in Tennessee under special liscense. Growers outside of Tennessee are on a waitlist and when budwood comes available, there will be increasing numbers of growers, and the eastern dogwood will be guaranteed a continuing presence among gardeners.One source that ships "Appalachian Spring" nationwide even to individual gardeners is a central Tennessee grower:
Korean dogwood is not very susceptible to the fungus & other gardened varieties are also relatively safe. Hybrids of of the Korean with the Eastern dogwood have been developed for gardeners, but these do not help save the trees in the wild. Some C. florida x kousa dogwoods now being produced for gardens bare the cultivar names "Celestial" "Aurora" "Stardust" & "Ruth Ellen," among others released from the Rutgers University experimental station. They're bred for both mildew & anthracnose resistance, but as young trees most of them have been found to be a little less resistant than would be optimal, & for a serious level of resistance, "Appalachian Spring" is thus far the ONLY reliable cultivar, with U.of T. expecting other resistant strains to be developed from it & not with the assistance of C. kousa hybridization.
The western dogwood, alas, is very susceptible, & Northwest forests were afflicted slightly earlier than the eastern (but by a strain of anthracnose distinct from that in the east & believed to have been independently introduced into North America). No one is as yet producing a western dogwood equivalent of "Appalachian Spring." There is some fear that the C. nuttallii could eventually be extinct without herculean efforts to save it, and micropropogation of several strains from several location is being undertaken by a C. nuttallii gene preservation program in British Columbia. More research into the problem has been done in the east not because C. florida is more susceptible, but because it had become a major multi-million dollar component of the nursery industry, whereas C. nuttalli seemingly does not have the same degree of economic significance. However, on the plus side, anthracnose decimation seems to have peaked in the late 1980s and early 1990s, and surviving trees today are a LITTLE less susceptible to the disease. In some forests only 15 to 20% of the dogwoods were killed, in other areas nearly all were killed, so degree of decimation is not uniform. Usually the remaining trees in a wild dogwood population WILL be infected but the hope is that enough will survive & reproduce in the wild to perpetuate their own generations until eventually only resistant trees remain, at which point they may be able to increase in number rather than continue to decline in numbers. Natural regeneration of self-seeding infected dogwoods has been observed in a limited sort of way in the east, and may be happening with the western dogwood too.
Wild trees in the more sun-exposed sites last longest (despite that the tree would prefer to be sub-story) because the disease spreads more slowly in dry heat. Gardened cultivars can sometimes be saved if the fungus is spotted soon enough, if infected branches are removed and properly disposed of, if the tree is not watered in the spring time when the fungus is most active, but not permitted to experience drought in the summer, and by watering exclusively in the morning as the fungus can be assisted in its spread by evening watering even in summer. Fungicides are not ineffective on their own, but are nevertheless sometimes used as a confinement technique & to stop spread of spoors at time of spring budding.
Another disease has of late been introduced into the Pacific Northwest which afflicts rhododendrons and oaks is Phytopthera ramorum. In Oregon a serious attempt is being made to nip it in the bud so to speak, but the disease is also making inroads into Washington state without much being done. In Oregon rhododenron growers have a bit more political power because they contribute more profoundly to the state economy; Washington rhody growers are not so empowered. And unless both states get on top of it together, everyone may be very sorry a few years from now, if one of the greatest symbols of the northwest begins to die off. The disease has some capacity to afflict Douglas fir, which has a mightier economic power in Washingotn, but for so long as it seems mostly to be restricted to garden ornamental shrubs & oaks, Weyerhauser is not going to be pressuring the economically strapped state into doing something about Phytopthera. Some of us northwesterners who always loved dogwoods & rhodies are already pondering what we're gonna have to love instead!
-paghat the ratgirl
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