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| | [[Image:GardenValerian.jpg|thumb|220px|right|[[Red Valerian]], a perennial plant.]] | | [[Image:GardenValerian.jpg|thumb|220px|right|[[Red Valerian]], a perennial plant.]] |
| | + | Of three or more season cycles' duration.{{SCH}} |
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| − | A '''perennial plant''' or '''perennial''' ([[Latin]] ''per'', "through", ''annum'', "year") is a [[plant]] that lives for more than two [[year]]s. Perennial plants are divided into two large groups, those that are woody and those that are [[herbaceous]]. All woody plants are perennials since they form [[wood]]y tissue that persists from one year to the next. ''Woody perennials'' develop a woody base or root system from which the foliage and flower stems grow year after year while the plant is alive. In common usage the term perennial generally describes herbaceous perennials. Since herbaceous plants as a group include all non woody plants, they can be annuals, biannual and/or perennials. Perennial plants are a diverse group, they can be short lived, living for only a few years or they can be long lived persisting for 20 or more years with some woody plants living for over 1,000 years. Perennial plants can vary in size from only a few millimeters in size to over 100 meters tall. They include a wide assortment of plant groups from [[fern]]s and [[liverwort]]s to the highly diverse flowering plants like [[Orchid]]s and [[Grass]]es.
| + | Perennials tend to live from year to year, as opposed to annuals and biennials, which die root and branch after flowering and fruiting{{SCH}}. Annuals live only one year, biennials two years{{SCH}}. Perennials include trees, shrubs and herbs, the two former being woody, the latter not{{SCH}}. "Perennials," as commonly used by gardeners, is a convenient shortening of the phrase "hardy herbaceous perennials," which includes peony, phlox and other non-woody plants whose roots live over the winter while their tops may die to the ground{{SCH}}. The phrase "hardy herbaceous perennials" is also shortened in common speech to "herbaceous plants;" or one speaks of the "hardy border."{{SCH}} |
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| − | Perennials that flower and fruit only once and then die are termed '''''[[monocarpic]]''''' or [[semelparous]]. However, most perennials are '''''[[polycarpic]]''''', flowering over many seasons in their lifetime.
| + | A popular fallacy about perennials lies in the common statement that "they die down every year and come up again in the spring."{{SCH}} Many of them never come up after two or three years of flowering; that is, perennials are not necessarily perpetual{{SCH}}. Peonies may be as long-lived as shrubbery, and a clump of fraxinella has been known to outlive father, son, and grandson in the same spot{{SCH}}. But these are exceptions{{SCH}}. The general practice with perennials is to divide them every second or third year{{SCH}}. Nearly all hardy herbaceous plants should be lifted now and then, because the crowns that give the flowers in most desirable kinds flower only two or three seasons and then die; but the plant may be continually spreading and making new growths, which furnish the flowers, and, unless lifted and divided, the stocks become scattering and unattractive{{SCH}}. Another very good reason for lifting and dividing the perennials is that, being mostly strong-rooted plants, they deplete the soil; when shifted, they are likely to be set in a new place{{SCH}}. |
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| − | Perennials typically grow structures that allow them to adapt to living from one year to the next. These structures include bulbs, tubers, woody crowns, rhizomes plus others. They might have specialized stems or crowns that allow them to survive periods of dormancy over cold or dry seasons during the year. While annuals produce seeds to continue the species as a new generation while the growing season is suitable and the seeds survive over the cold or dry period to begin growth when the conditions are again suitable.
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| − | Many perennials have specialized to survive under extreme environmental conditions, some have adapted to survive hot dry conditions, or to survive under cold temperatures. Those plants tend to invest a lot of resource into there adaptations and often do not flower and set seed until after a few years of growth. Many perennials produce relatively large seeds, large seeds can have an advantage, with larger seedlings produced after germination that can better compete with other plants or more quickly develop leaves for photosynthesis. Annuals tend to produce many more seeds per plant since they will die at the end of the growing season, while perennials are not under the same pressure to produce large numbers of seeds but instead the same plant can produce seeds over many years. | |
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| − | In warmer and more clement [[climate]]s, perennials grow continuously. In seasonal climates, their growth is limited to the growing season. For example, in temperate regions a perennial plant may grow and bloom during the warm part of the year, with the foliage dying back in the winter. These plants are [[deciduous]] perennials. Regrowth is from existing stem tissue. In many parts of the world, seasonality is expressed as wet and dry periods rather than warm and cold periods. In some species, perennials retain their foliage all year round; these are '''[[evergreen]]''' perennials.
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| − | With their roots protected below ground in the soil layer, perennial plants are notably tolerant of [[wildfire]]. They are also less subject to extremes of cold in temperate and arctic winters, with less sensitivity than trees or shrubs.
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| − | Perennial plants dominate many natural [[ecosystem]]s on land and in fresh water, with only a very few (e.g. ''[[Zostera]]'') occurring in shallow sea water. They are particularly dominant in conditions too fire-prone for trees and shrubs, e.g., most plants on [[prairie]]s and [[steppe]]s are perennials; they are also dominant on [[tundra]] too cold for tree growth. In [[forest]]s, perennial plants are of secondary importance to trees and shrubs, but are often still abundant on the forest floor.
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| − | Perennial plants are usually better competitors than annual plants, especially under stable, resource-poor conditions. This is due to the development of larger [[root]] systems which can access water and soil nutrients deeper in the soil and to earlier emergence in the spring.
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| − | Examples of evergreen perennials include ''[[Begonia]]'' and [[banana]].
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| − | Examples of deciduous perennials include [[goldenrod]] and [[mint]].
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| − | Examples of monocarpic perennials include ''[[Agave]]'' and some species of ''[[Streptocarpus]]''.
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| | ==See also== | | ==See also== |
| | *[[Annual plant]] | | *[[Annual plant]] |
| | *[[Biennial plant]] | | *[[Biennial plant]] |
| − | *[[Perennial Tea Ceremony]]
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| | *[[Herbaceous]] | | *[[Herbaceous]] |
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| − | ==External links==
| + | {{glossary}} |
| − | * [http://extension.oregonstate.edu/mg/botany/cycles.html Plant life cycles]
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| − | * [http://www.usna.usda.gov/Hardzone/ushzmap.html USDA Plant Hardiness Zone Map]
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| − | * [http://www.urbanext.uiuc.edu/perennials/ Gardening with Perennials]
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| − | [[Category:Plants]]
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| − | [[Category:Botany]]
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| − | [[Category:Gardening]]
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Of three or more season cycles' duration.CH
Perennials tend to live from year to year, as opposed to annuals and biennials, which die root and branch after flowering and fruitingCH. Annuals live only one year, biennials two yearsCH. Perennials include trees, shrubs and herbs, the two former being woody, the latter notCH. "Perennials," as commonly used by gardeners, is a convenient shortening of the phrase "hardy herbaceous perennials," which includes peony, phlox and other non-woody plants whose roots live over the winter while their tops may die to the groundCH. The phrase "hardy herbaceous perennials" is also shortened in common speech to "herbaceous plants;" or one speaks of the "hardy border."CH
A popular fallacy about perennials lies in the common statement that "they die down every year and come up again in the spring."CH Many of them never come up after two or three years of flowering; that is, perennials are not necessarily perpetualCH. Peonies may be as long-lived as shrubbery, and a clump of fraxinella has been known to outlive father, son, and grandson in the same spotCH. But these are exceptionsCH. The general practice with perennials is to divide them every second or third yearCH. Nearly all hardy herbaceous plants should be lifted now and then, because the crowns that give the flowers in most desirable kinds flower only two or three seasons and then die; but the plant may be continually spreading and making new growths, which furnish the flowers, and, unless lifted and divided, the stocks become scattering and unattractiveCH. Another very good reason for lifting and dividing the perennials is that, being mostly strong-rooted plants, they deplete the soil; when shifted, they are likely to be set in a new placeCH.
See also
