{"id":8729,"date":"2017-01-01T12:00:55","date_gmt":"2017-01-01T17:00:55","guid":{"rendered":"http:\/\/www.whatgrowsthere.com\/grow\/?p=8729"},"modified":"2016-08-05T10:08:44","modified_gmt":"2016-08-05T14:08:44","slug":"southern-gardeners-should-use-the-ahs-heat-zone-map","status":"publish","type":"post","link":"https:\/\/whatgrowsthere.com\/grow\/2017\/01\/01\/southern-gardeners-should-use-the-ahs-heat-zone-map\/","title":{"rendered":"Southern Gardeners Should Use The AHS Heat Zone Map"},"content":{"rendered":"
\"Balloon<\/a>

Balloon flower (Platycodon) rated AHS 8-1<\/p><\/div>\n

\"AHS<\/a>

AHS Heat Map<\/p><\/div>\n

The AHS Heat Zone Map isn’t new. The American Horticultural Society developed it in 1960 and updated it in 1990. It has become an important\u00a0reference for knowing\u00a0both the cold and heat tolerances of garden plants. Many perennials in southern U.S. gardens struggle in\u00a0the extreme heat and humidity.<\/p>\n

The heat zone map developed by AHS is based on heat, rather than cold, to determine a plant’s ability to survive in a specific location. It uses summer temperatures to demonstrate a specific plant\u2019s ability to survive or handle the stress of high summer temperatures.<\/p>\n

The U.S. Heat Zone Map is divided 12 zones. Each is derived from the number of “heat days” or the number of days the temperatures at 86\u00baF or higher. Each zone is identified by the average number of heat days it experiences in a year.<\/p>\n

Heat zones are expressed with the highest heat zones listed first, followed by the lowest. For example, the heat zone rating for balloon flower (Platycodon<\/em>) is AHS Heat Zone 8-1. This illustrates that Platycodon<\/em> can tolerate and survive the summer heat in zones 1 through 8 (or 8 through 1). Sweetgum (Liquidambar styraciflua<\/em>) is rated USDA hardiness\u00a06 to 9, and AHS heat 9 to 6.\u00a0A\u00a0plant is listed as having AHS Heat Zone: 9-5, the growing season may be too short or summer temperatures not high enough\u00a0for\u00a0plants to flower in zones 1 to 4.<\/p>\n

Several environmental factors, such as water, light, daylength, oxygen, and air circulation and pollutants,\u00a0can skew the accuracy of a particular heat zone. Amount of rainfall\u00a0is the most critical; plants lacking water are more susceptible to injury from heat.<\/p>\n

Some plants vary in the ability to withstand heat, not only from species to species but even among individual plants of the same species! Unusual seasons- fewer or more hot days than normal- will invariably affect results in your garden. Sometimes, individual\u00a0plant cultivars may\u00a0survive outside their designated heat zone.<\/p>\n

The AHS Heat Zone Map is intended to supplement the USDA Hardiness Zone Map, permitting\u00a0gardeners to select\u00a0plants based on their ability to survive seasonal temperature extremes in their region. Unfortunately, many\u00a0plant labels (tags)\u00a0still do not list their\u00a0heat tolerance.<\/p>\n","protected":false},"excerpt":{"rendered":"

The AHS Heat Zone Map isn’t new. The American Horticultural Society developed it in 1960 and updated it in 1990. It has become an important\u00a0reference for knowing\u00a0both the cold and heat tolerances of garden plants. Many perennials in southern U.S. gardens struggle in\u00a0the extreme heat and humidity. The heat zone map developed by AHS is […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[800,1208,774,627,606,1320,729,603,630,646,781,7,1,455,642],"tags":[],"_links":{"self":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts\/8729"}],"collection":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/comments?post=8729"}],"version-history":[{"count":6,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts\/8729\/revisions"}],"predecessor-version":[{"id":8951,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts\/8729\/revisions\/8951"}],"wp:attachment":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/media?parent=8729"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/categories?post=8729"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/tags?post=8729"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}