{"id":2715,"date":"2019-05-09T00:04:03","date_gmt":"2019-05-09T07:04:03","guid":{"rendered":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-503\/"},"modified":"2024-11-13T15:04:05","modified_gmt":"2024-11-13T23:04:05","slug":"diagnosing-rhododendron-problems","status":"publish","type":"pal","link":"https:\/\/depts.washington.edu\/hortlib\/pal\/diagnosing-rhododendron-problems\/","title":{"rendered":"diagnosing rhododendron problems"},"content":{"rendered":"<p><strong>The edges of the leaves on one of my rhododendrons are turning brown and<\/strong><br \/>\n<strong>crispy. This condition advances toward the midline until the leaf dies. My older, more established rhododendrons are looking fine. All have flowered this spring.<\/strong><\/p>\n<p>&nbsp;<\/p>\n<p>We can&#8217;t diagnose the problem via e-mail. However, what you describe could be a couple of things.<\/p>\n<p>It might be marginal leaf necrosis which can be caused by cold damage, and made worse by wind and drought; by drought while the plant is in active growth; by high<br \/>\namounts of salt in the soil, often due to overuse of soluble fertilizers,<br \/>\nand seen often if plant is located close to the house, where the eaves<br \/>\nprevent rainwater from reaching the soil. Other causes are poor drainage,<br \/>\nplanting too deep, root damage, root weevils, nutrient deficiency, or<br \/>\ndisease. (Source: <a href=\"http:\/\/hortlib.kohacatalog.com\/cgi-bin\/koha\/opac-detail.pl?biblionumber=3966\">How to Identify Rhododendron and Azalea Problems,<\/a><br \/>\nWashington State University Cooperative Extension, 1984).<\/p>\n<p>There are descriptions and illustrations of rhododendron problems on the HortSense website of <a href=\"https:\/\/hortsense.cahnrs.wsu.edu\/ornamentals\/\">Washington State University Extension<\/a>.<\/p>\n<p>For comparison purposes, see the lists of diseases and problems affecting<br \/>\nRhododendrons from <a href=\"https:\/\/ipm.ucanr.edu\/PMG\/GARDEN\/PLANTS\/rhododendron.html\">University of California, Davis Integrated Pest Management Online.<\/a> To get a definitive answer, it may be a good idea to take samples of the<br \/>\naffected leaves to a Master Gardener Clinic for diagnosis.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The edges of the leaves on one of my rhododendrons are turning brown and crispy. This condition advances toward the midline until the leaf dies. My older, more established rhododendrons are looking fine. All have flowered this spring. &nbsp; We can&#8217;t diagnose the problem via e-mail. However, what you describe could be a couple of things. It might be marginal leaf necrosis which can be caused by cold damage, and made worse by wind and drought; by drought while the&#8230;<\/p>\n<div><a class=\"more-link\" href=\"https:\/\/depts.washington.edu\/hortlib\/pal\/diagnosing-rhododendron-problems\/\">Continue reading <span class=\"screen-reader-text\">diagnosing rhododendron problems<\/span><\/a><\/div>\n","protected":false},"author":4,"featured_media":0,"menu_order":0,"template":"","keyword":[475],"class_list":["post-2715","pal","type-pal","status-publish","hentry","keyword-rhododendrons-diseases-and-pests"],"acf":[],"_links":{"self":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal\/2715"}],"collection":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal"}],"about":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/types\/pal"}],"author":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/users\/4"}],"wp:attachment":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/media?parent=2715"}],"wp:term":[{"taxonomy":"keyword","embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/keyword?post=2715"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}