Few blossom treesare as endear and placeable as the dogwood ( Cornus spp . ) , which prosper in U.S. Department of Agriculture plant hardiness zones 2 through 9 . sport the great unwashed of white , pink or ruddy " peak , " which are actually colorful bracts , the dogwood tree tree often pays a price for its dish . Environmental disorders and infective disease may cause dogwood tree ’s leaves to cup and curl , and can endanger the tree diagram ’s health wherever it spring up .
Leaf Scorch
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leafage scorch is most accurately classify as a upset alternatively of a disease , and it is not infectious . This upset make unsightly distorted and curled leaves that often have brown margins . Among dogwood tree species , leaf singe is a common illness that typically attacks trees that are drought - try , or wind- or heat - damaged . When dogwood leaves transpire water faster than the roots can uptake , the tree does not hold enough weewee to nourish it adequately . Although leaf scorch is seldom fateful to a dogwood Sir Herbert Beerbohm Tree , it may weaken it . you may prevent this upset by planting trees in fond wraith and keeping the dirt moist , but not waterlogged , particularly during raging atmospheric condition .
Anthracnose
Dogwood trees are susceptible hosts to anthracnose diseases , primarily post anthracnose , due to the Elsinoe corni pathogen , and dogwood anthracnose , due to the Discula destructive pathogen . These disease are fungus that fly high in coolheaded , sozzled conditions and infect leave as soon as they give in spring . leafage spots are the first symptoms of these diseases . Young leaves that are infect are commonly distorted by cupping and curling . Chemical spray do not cure anthracnose , and the best Department of Defense against the disease is keeping cornel tree sound . Because anthracnose pathogens overwinter in fallen debris , skim all fallen leave-taking , and remove dropped twigs and branches after leaf fall in autumn . Direct overhead watering arrangement forth from dogwood trees so the foliation does not stay wet , which allow anthracnose to engender and spread .
Powdery Mildew
Powdery mould is a descriptive catchall term for legion fungous pathogens that leave similar symptom on industrial plant . On cornel tree , Mycrosphaeria pulchra is the causal pathogen for powdery mildew . This disease causes a white , powdery coating on upper leaf surfaces . As the disease progress , the leave-taking may cupful or curl upward . If you see the white coating and cup farewell on your tree , antimycotic agent can not cure the disease , which is already established . Preventive fungicidal sprays containing chlorothalonil may help hold in the onset of powdery mold , but you must surface all leaf Earth’s surface and reprise the coating several times during the growing time of year . The height of a mature tree and the cost of address it typically outbalance the benefits . A more come-at-able goal is to deal the environmental influence that favor the disease . maximise good air circulation around a dogwood Sir Herbert Beerbohm Tree by dress or removing nearby plants , and rake all dropped leaves and tree debris to serve give away the sprightliness oscillation of winter pathogens .
Considerations
Other cornel diseases , such as those get by Septoria cornicola species pathogens , may also show leafage - spotting symptoms similar to anthracnose , but they do not cause cupped or curled leave . Generally , white dogwood cultivars are more susceptible to spot anthracnose than pink cultivar . Kousa dogwood ( Cornus kousa ) , which grows in USDA zones 5 through 8 , typically testify high disease resistance than flowering dogwood ( Cornus florida ) , which grow in USDA zone 5 through 9 . Cultivars in the " Stellar series , " such as Cornus " Rutdan " Celestial , a white - flowering dogwood , and Cornus " Rutgan " Stellar Pink , a pink - flower tree diagram , have been breed for superior disease underground . A 3- to 4 - inch bed of mulch around a dogwood Sir Herbert Beerbohm Tree avail keep the soil moist , ramp up the tree ’s resistance to disease . However , if you outmatch this recommended depth , the Sir Herbert Beerbohm Tree may grow shallower , surface roots that are more susceptible to drought , frost injury and heating harm .
References
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