Learn how to Establish and Deal with Widespread Dogwood Illnesses

Nice power is commonly paired with important weak point.

The mighty Superman is weakened by Kryptonite, a robust vampire is burned by daylight, and a beautiful dogwood can maintain injury from quite a lot of illnesses.

A close up vertical image of the pink and white blooms of a flowering dogwood tree growing in the garden. To the center and bottom of the frame is green and white printed text.

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For The Man of Metal and vampires, stopping hurt is so simple as avoiding publicity.

However save for the occasional transplanting, species of dogwood are caught in place, and escape from illness just isn’t an choice.

Whereas these vegetation aren’t utterly helpless – they can launch immune responses to pathogens – it’s as much as us gardeners to maintain our dogwoods as wholesome as potential.

However how? How can a inexperienced thumb deal with a diseased dogwood? And the way can one maintain these illnesses from hanging within the first place?

All these questions and extra are answered on this information. Upon studying it, you’ll be greater than prepared to keep up the well being and vibrant look of your dogwoods for the lengthy haul.

Let’s get to it:

Every of the next illnesses include their very own causal pathogens, signs, and administration methods.

However there are undoubtedly some normal practices that’ll assist maintain your dogwoods wholesome, irrespective of the actual illness that they face.

Select solely wholesome seeds, cuttings, and transplants to be used in your backyard. Make sure you use disease-free soils, and all the time sterilize your instruments earlier than making any pruning cuts.

However the above ideas received’t make a lot of a distinction in case your vegetation aren’t nicely cared for, or in the event that they aren’t positioned within the right spot to start with.

Be certain that your dogwoods are given the correct publicity, soil, irrigation, and fertilization, located in hardiness zones that they’re fitted to.

All of this, after all, is dependent upon the species that you just’re cultivating.

1. Armillaria Root Rot

Dogwood illnesses are available many alternative kinds, and Armillaria root rot, attributable to fungi within the Armillaria genus, is a very nasty one.

A close up horizontal image of the symptoms of armillaria root rot at the base of a landscape tree.
Photograph by Joseph OBrien, USDA Forest Service, Bugwood.org, by way of CC BY-SA.

After the onset of an infection, illness signs manifest themselves everywhere in the plant. Troubled leaves flip yellow, are smaller than regular, and prematurely drop.

Branches die again, gentle fungal threads lie beneath the crown’s bark, darkish fungal strands lie on or within the soil, and honey-hued mushrooms develop close to the tree’s base in autumn.

There’s no recognized treatment, and after the tree inevitably declines and finally dies, you’ll finally need to take away and destroy the contaminated specimen.

And for the reason that fungal pathogens can persist within the soil for years, you received’t be capable of use the identical rising web site for a great lengthy whereas, at the least not till you sanitize or solarize it.

A close up horizontal image of Armillaria honey fungus growing on a tree stump.

Prevention is greatest achieved by not doing sure issues. Don’t place dogwoods in poorly-draining soil, irrigate excessively, or injury the timber.

And since this pathogen is commonly present in newly-cleared soils, avoiding planting in mentioned soils for at the least a 12 months is commonly really useful.

2. Botrytis Blight

Attributable to numerous fungal species throughout the Botrytis genus, Botrytis blight afflicts dogwoods and an assortment of species from different genera, similar to begonias, chrysanthemums, and tulips.

Overwintering in useless plant particles, the causal fungi kind spores in springtime, which unfold by way of air currents and/or splashed water onto flower bracts and leaves.

Any contaminated buildings are left with brown, wrinkled, and irregularly-shaped patches of tissue. In moist and humid bouts of cool climate, grey mould can kind over these patches, therefore the illness’s nickname “grey mould.”

A close up of gray mold on the surface of a leaf.

As you possibly can think about, these issues result in irregular development and improvement of the bothered buildings, and previous flowers are liable to rotting quickly.

Since heat, dry climate halts the illness earlier than it will probably flip severe, any an infection will most definitely be a brief beauty difficulty.

For prevention, rake up and eliminate close by plant detritus, which is able to eradicate the fungi’s overwintering websites. Prune away contaminated tissues to sluggish additional unfold.

To permit for ample moisture-drying airflow, correctly area out vegetation and prune throughout the cover.

A close up horizontal image of a dogwood flower pictured on a soft focus background.

Keep away from splashing the flowers and foliage with water to stop extra moisture, and don’t over-fertilize with nitrogen, which might stimulate the expansion of tender, susceptible tissues.

For added prevention, apply fungicides each 10 days throughout vulnerable durations in spring. Copper, sulfur, and Captan are all high quality selections.

3. Crown Canker

The trademark symptom of this illness is within the identify: a discolored, oozing canker on the tree’s crown close to the soil line.

In time, the canker turns into increasingly more sunken and uncovered because the bark falls away, and might girdle the trunk or root crown. Finally, the tree can weaken, turn out to be vulnerable to different pathogens, and even perish.

A close up horizontal image of the diseased bark on a landscape tree.

However earlier than all that happens, you’ll most likely discover diminished vigor and decreased foliage – each in measurement and in quantity.

Extra leaf signs embrace a lighter-than-normal hue, untimely drop and colour change, and general distortion.

An contaminated tree could even produce extra flowers than common, which is an uncommon manner to answer an infection. Twigs and branches may die again.

The causal pathogen, Phytophthora cactorum, overwinters in plant particles, spreads by way of wind or water, and usually enters the tree by way of trunk wounds, however it will probably additionally enter the basis system.

For prevention, keep away from wounding the trunk throughout transplanting and garden care, because the smallest of vulnerabilities can result in whole demise, Loss of life Star-style.

Equally to Botrytis blight, you shouldn’t splash the leaves and flowers with water or depart plant particles close by.

A close up horizontal image of light pink and white dogwood flowers pictured on a soft focus background.

In case your fingers are regular and you’ve got a pointy blade, be happy to take away small cankers from the trunk during times of dry climate in summer season.

To take action, take away all of the diseased bark and sapwood you possibly can, in addition to two further inches of wholesome tissue as insurance coverage. After the surgical procedure, depart the world uncovered to dry air.

If an an infection spreads all through the vast majority of the tree, it’s best to excavate and pitch it.

4. Discula Anthracnose

Portobello mushrooms, hallucinogenic ‘shrooms, the crimson and inexperienced mushrooms from “Tremendous Mario Bros.,” – there are many well-known fungi on the market.

To take a better have a look at a fairly notorious one, let’s flip our consideration to the Discula destructiva fungus.

A close up horizontal image of a dogwood tree infected with anthracnose.

Discula anthracnose, or dogwood anthracnose, each names for the illness attributable to this fungus, is arguably probably the most harmful illness for a dogwood.

After its arrival within the US from components unknown, the illness has considerably harmed and decreased native dogwood populations throughout the nation, so it undoubtedly warrants being taken significantly.

After timber leaf out in late spring, spots first kind on contaminated leaves and flower bracts on decrease branches earlier than transferring up the cover.

These spots are tan to brown, with brown to reddish-purple margins, and are usually adopted by sunken brown cankers because the illness spreads into the tree’s woody tissues.

Mentioned cankers can girdle twigs, branches, and the trunk, all of which finally kills the tree usually.

The illness spreads by way of spores produced throughout the leaf spots which might be dispersed by bugs, birds, or splashes of water. Shifting contaminated specimens into new landscapes may result in unfold.

Stopping Discula anthracnose requires a multi-pronged method.

Keep away from shade and extra moisture by planting timber in sunny areas avoiding splashing the foliage and flowers.

Rake up fallen plant particles, and prune away water sprouts, that are liable to an infection.

Any contaminated tissues needs to be pruned away as you occur to note them. Burn them to stop additional unfold, or eliminate them within the trash.

Beginning at bud break, you possibly can apply fungicides each two weeks till the leaves are totally grown.

Moreover, you may wish to select resistant plantings from the get-go, such because the kousa dogwood and hybrids from the Stellar sequence like ‘Aurora,’ ‘Ruth Ellen,’ and ‘Star Mud.’

Even the vulnerable flowering dogwood has a couple of resistant cultivars – search for ‘Appalachian Spring,’ ‘Cherokee Sundown,’ and ‘Spring Grove.’

In case your tree is a goner, take away and destroy it.

A square image of a kousa dogwood tree growing in a garden border outside a residence.

Kousa Dogwood

For the standard kousa dogwood that’s obtainable in one- to five-foot beginning sizes, go to Planting Tree.

5. Fungal Leaf Spot

Attributable to both Cercospora cornicola or Septoria cornicola fungi, fungal leaf spot primarily happens throughout moist summers.

A close up horizontal image of dogwood foliage with holes and lesions as a result of infection, pictured on a soft focus background.

Whatever the causal pathogen, the illness signs are fairly related: the leaf spots are 1 / 4 to an eighth of an inch in diameter, with sharp and irregularly-shaped borders.

Cercospora spots are tan to brown, whereas Septoria spots are a darkish brownish-purple that later lightens or turns grey.

Severely contaminated leaves can drop prematurely, and a number of seasons of leaf spot can weaken timber, leaving them vulnerable to different points.

Because the fungi overwinter in fallen leaves, these needs to be raked up and disposed of.

Making use of fungicides preventatively at bud break might be useful, particularly in case your tree is especially in danger or already contaminated with fungal leaf spot.

6. Powdery Mildew

Attributable to Erysiphe pulchra or Phyllactinia guttata, powdery mildew is a fungal illness that leaves foliage and tender new development coated with a high quality white powder.

It usually happens throughout summer season and fall in spots the place air circulation is poor.

Secondary signs embrace chlorosis, reddish discoloration, marginal leaf scorch, untimely defoliation, and patches of useless tissue.

A close up horizontal image of a leaf suffering from powdery mildew.

If powdery mildew strikes in late summer season, the influence is often minimal.

The potential for early-season infections in specimens that you just’re keen on can justify the usage of fungicides, however your first step needs to be raking up close by leaf and twig particles.

Moreover, prune away useless or contaminated tissues as you discover them.

A close up vertical image of dogwood foliage with a light dusting of powdery mildew on the surface.

For powdery mildew-resistant plantings, attempt specimens from the aforementioned Stellar sequence, together with kousa dogwood cultivars similar to ‘Milky Manner,’ ‘Milky Manner Choose,’ and ‘Nationwide.’

Sturdy flowering dogwood cultivars embrace ‘Appalachian Pleasure,’ ‘Appalachian Blush,’ ‘Appalachian Snow,’ and ‘Appalachian Mist.’

7. Spot Anthracnose

As if one sort of anthracnose wasn’t dangerous sufficient…

Elsinoe corni is the fungus accountable for this one. Surviving for years on contaminated tissues, the pathogen primarily strikes in moist spring situations, leaving flower bracts, leaves, and fruits with tan spots ringed with reddish-purple.

A close up horizontal image of the white bracts of a dogwood infected with anthracnose pictured on a soft focus background.

In extreme infections, bothered buildings can turn out to be wrinkled and warped, and the small spots an eighth of an inch in diameter merge into bigger spots.

To handle this illness, prune contaminated tissues and rake up fallen plant particles. You possibly can’t management the climate to make situations much less moist, however you can enhance inter-canopy airflow by way of pruning.

Equally to Discula anthracnose, you possibly can apply fungicides at bud break by way of full leaf growth as a preventative measure in specimens contaminated the earlier 12 months.

A horizontal image of the branches and blooms of a flowering dogwood tree pictured on a blue sky background.

The illness often doesn’t kill the tree, however it will probably depart dogwoods weakened and deformed.

As potential alternative choices, resistant plantings embrace the ‘Nationwide’ and ‘Milky Manner Choose’ kousa cultivars, in addition to the ‘Cherokee Courageous,’ ‘Cherokee Chief,’ ‘Welch’s Bay Magnificence,’ ‘Cherokee Princess,’ and ‘Springtime’ flowering dogwood cultivars.

‘Cherokee Courageous’ and ‘Cherokee Princess’ can be found from Nature Hills Nursery, whereas ‘Cherokee Chief’ and ‘Milky Manner’ might be bought from Quick Rising Bushes.

A Dogwood’s Well being Is Its Wealth

A panorama tree just like the dogwood seems its greatest when it’s wholesome. By stopping and managing illness correctly, you possibly can assist to maintain yours in mint situation.

A close up horizontal image of pink and white dogwood flowers pictured on a soft focus background.

Don’t see an contaminated dogwood as a tragedy, however fairly as a lesson.

By studying from our errors, we are able to be sure that we don’t make the identical ones once more sooner or later, and turn out to be higher gardeners alongside the best way.

Inquisitive about points of those dogwood illnesses that I didn’t contact on? Drop us a line within the feedback part beneath.

Keen on rising dogwoods, now that you just’re able to maintain them wholesome? Listed here are some improbable species to start out with:

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