{"id":2878,"date":"2019-10-10T00:06:46","date_gmt":"2019-10-10T07:06:46","guid":{"rendered":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-179\/"},"modified":"2023-08-08T11:14:03","modified_gmt":"2023-08-08T18:14:03","slug":"pal-question-179","status":"publish","type":"pal","link":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-179\/","title":{"rendered":"rhododendrons and autumn frosts"},"content":{"rendered":"<p><strong>A friend in Illinois has sent a photo this spring of a very healthy looking rhododendron &#8211; leaf buds fully elongated and beginning to unfurl, while the green, blunt flower buds remain unopened. The flower buds don&#8217;t look brown, diseased, frozen or injured, but they remain tightly closed, foliage bud growth preceding blooming. He says he has 6 plants doing the same this month. Possible reason?<\/strong><\/p>\n<p>Though we can&#8217;t diagnose plant problems by phone\/email, early autumn frosts can inhibit flowering and not all buds are equally affected.<\/p>\n<p>&#8220;Autumn frosts: These can lead to damage&#8230;if they either occur in early autumn or immediately after a late season warm spell. Continental climates with extremes of heat and cold are more likely to suffer sudden temperature changes than those with maritime climates&#8230;A sudden temperature drop will catch a plant before it has had a chance to reach maximum hardiness and it may suffer accordingly, even if normally perfectly able to withstand such a temperature in mid-winter&#8230;Speed of ripening varies considerably&#8230;There is also a variation in the hardiness of flower buds compared to foliage and growth buds. Commonly, flower buds may be as much as 10 F. less hardy than foliage&#8230;&#8221;<br \/>\n(Source: <i>The Cultivation of Rhododendrons,<\/i> by P. Cox, 1993, p. 119-120)<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A friend in Illinois has sent a photo this spring of a very healthy looking rhododendron &#8211; leaf buds fully elongated and beginning to unfurl, while the green, blunt flower buds remain unopened. The flower buds don&#8217;t look brown, diseased, frozen or injured, but they remain tightly closed, foliage bud growth preceding blooming. He says he has 6 plants doing the same this month. Possible reason? Though we can&#8217;t diagnose plant problems by phone\/email, early autumn frosts can inhibit flowering&#8230;<\/p>\n<div><a class=\"more-link\" href=\"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-179\/\">Continue reading <span class=\"screen-reader-text\">rhododendrons and autumn frosts<\/span><\/a><\/div>\n","protected":false},"author":4,"featured_media":0,"menu_order":0,"template":"","keyword":[69,403,36],"class_list":["post-2878","pal","type-pal","status-publish","hentry","keyword-frost","keyword-hardy-plants","keyword-rhododendron"],"acf":[],"_links":{"self":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal\/2878"}],"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=2878"}],"wp:term":[{"taxonomy":"keyword","embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/keyword?post=2878"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}