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208:(USDA) system of hardiness zones based on average minimum yearly temperatures. This system was developed specifically for the extremely diverse range of conditions in the US, from baking desert to frozen tundra. Another commonly used system is the Sunset Climate Zone system. This system is much more specific to climates (i.e. precipitation, temperature, and humidity based) and less dependent on the yearly minimum.
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outdoor plants in the UK fall within the range H4, −10 to −5 °C (14 to 23 °F) (hardy in the average winter) to H5, −15 to −10 °C (5 to 14 °F) (hardy in a cold winter). Also, the average minimum temperature in the UK is much warmer than the average minimums in much of the northern US, while the average maximums in the northern US are often much warmer in summer than the UK.
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has published a set of hardiness ratings applicable to the UK. The ratings range from H1a to H7. H1a, higher than 15 °C (59 °F), applies to tropical plants permanently under glass in heat; while H7, below −20 °C (−4 °F), applies to very cold-tolerant plants such as heathers. Most
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In addition to cold tolerance, plant hardiness has been observed to be linked to how much stress specific plants are undergoing into the winter, or even how fast the onset of cold weather is in a specific year. This means that often stressed plants will exhibit less cold tolerance than plants that
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plants which are sown in heat in winter or early spring, and planted outside after all danger of frost has passed. "Fully hardy" usually refers to plants being classified under the Royal
Horticultural Society classifications, and can often cause confusion to those not using this method. When this
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are still poorly understood. Wind not only causes mechanical stress, but also makes the plant colder and dryer. Plants may evolutionally adapt to wind by becoming smaller (to avoid wind) or bigger (to resist the wind). Physiologically, the mechanical force also causes a cascade of signals in the
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Hardiness of a plant may be divided into two categories: tender, and hardy. Tender plants are those killed by freezing temperatures, while hardy plants survive freezing—at least down to certain temperatures, depending on the plant. "Half-hardy" is a term used sometimes in horticulture to
174:. Woody plants that survive lower temperatures are dehydrating their cells, allowing water to freeze between cell walls and the cells to survive. Plants normally considered hardy may not survive freezing if they are not readily acclimated, which renders them unable to use these mechanisms.
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Woody plants survive freezing temperatures by suppressing the formation of ice in living cells or by allowing water to freeze in plant parts that are not affected by ice formation. The common mechanism for woody plants to survive down to –40 °C (–40 °F) is
223:. This results in areas like western Scotland experiencing relatively mild winter conditions and cool summers that enable the growing of some subtropical plants, despite being well to the north of subtropical climate areas. The
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latitudes, the term most often describes resistance to cold, or "cold-hardiness", and is generally measured by the lowest temperature a plant can withstand.
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Plants vary greatly in their tolerance of growing conditions, and are capable of adaptation to changes in climate on their own to some extent. The
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Tolerance to other climatic factors are often omitted from the "hardiness" discussion. This section provides a very brief overview of the topics.
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have been well maintained. Plants may also die if the winter changes from balmy to exceptionally cold in a short period of time.
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are typically considered measurements of hardiness. Hardiness of plants is defined by their native extent's geographic location:
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distinction is made a fully tropical plant that requires hot temperatures to grow and display is termed a "tender" plant.
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510:"Submergence and Waterlogging Stress in Plants: A Review Highlighting Research Opportunities and Understudied Aspects"
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Hardy plants are generally known as plants that can tolerate a variety of extreme (both cold and hot) temperatures
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have an oceanic climate, and experience a narrower range of temperatures that is tempered by the presence of the
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may be displayed alongside cold-hardiness, such as in the
American Horticultural Society's "Heat Zones". See
661:"Differences between 1990 USDA Hardiness Zones and 2006 arborday.org hardiness zones reflect warmer climate"
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describes their ability to survive adverse growing conditions. It is usually limited to discussions of
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capable of withstanding particular climates forms an important part of
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Fukao, T; Barrera-Figueroa, BE; Juntawong, P; Peña-Castro, JM (2019).
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are dependent upon the cultivation of winter-hardy plants.
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243:, harsh environments, and poor or eroded soils, such as
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Interactive
Version of the 1990 USDA Hardiness Zone Map
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that specifies the climates in which they can survive.
149:– need cold winters to bloom, while others – such as
561:"Challenges to understand plant responses to wind"
451:"Guide to Climate Zones for Gardening in the West"
410:. Horticulture & Home Pest News. March 1, 1996
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200:Various hardiness ratings are published. In the
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41:adversity. Thus a plant's ability to tolerate
375:. London; New York: Expert Books. p. 4.
73:. These attributes are often simplified to a
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404:"How Woody Plants Survive Extreme Cold"
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646:"2006 arborday.org Hardiness Zone Map"
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294:Breeding for drought stress tolerance
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121:Winter-hardy plants grow during the
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279:Breeding for heat stress tolerance
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204:(US), the most widely used is the
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559:Onoda, Y; Anten, NP (July 2011).
275:Thermoregulation § In plants
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648:. National Arbor Day Foundation
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430:"USDA Plant Hardiness Zone Map"
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290:Drought § Impact on crops
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514:Frontiers in Plant Science
703:Agricultural terminology
369:Hessayon, D. G. (1996).
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145:. Some bulbs – such as
623:"RHS hardiness rating"
348:"How to be a gardener"
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585:10.4161/psb.6.7.15635
408:Iowa State University
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698:Plants by adaptation
627:RHS hardiness rating
453:. Sunset. 2021-05-18
577:2011PlSiB...6.1057O
327:Hardy Plant Society
303:, see cited review.
141:, and all kinds of
129:. Apart from hardy
346:Titchmarsh, Alan.
306:The mechanisms of
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95:selective breeding
382:978-0-903505-45-1
286:drought tolerance
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221:Gulf Stream
103:agriculture
692:Categories
667:2007-01-07
652:2007-01-07
636:9 November
494:2013-04-08
457:2021-06-14
436:2021-06-14
388:14 October
333:References
249:Cranesbill
165:Mechanisms
131:evergreens
215:(UK) and
186:Heather,
99:varieties
85:describe
79:temperate
71:elevation
63:longitude
31:Hardiness
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546:30967888
471:RHS 2017
354:24 April
316:See also
245:Milkweed
139:broccoli
67:latitude
55:flooding
39:climatic
594:3257795
573:Bibcode
537:6439527
520:: 340.
151:freesia
135:cabbage
127:dormant
87:bedding
51:drought
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288:, see
147:tulips
143:carrot
123:winter
35:plants
708:Crops
350:. BBC
77:. In
57:, or
638:2017
599:PMID
542:PMID
416:2014
390:2023
377:ISBN
356:2013
299:For
292:and
284:For
277:and
247:and
137:and
105:and
69:and
59:wind
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43:cold
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