- Perennial plant
A perennial plant or perennial (Latin "per", "through", "annus", "year") is a
plantthat lives for more than two years. [The Garden Helper. [http://www.thegardenhelper.com/planting.html The Difference Between Annual Plants and Perennial Plants in the Garden.] Retrieved on 2008-06-22.] When used as a noun, this term applies specifically to perennial herbaceous plants, even though woody plants like shrubs and trees are also perennial in their habit.
Perennials, especially small
flowering plants, grow and bloom over the spring and summer and then die back every autumn and winter, then return in the spring from their root-stockrather than seeding themselves as an annual plantdoes. These are known as "herbaceous perennials". However, depending on the rigors of local climate, a plant that is a perennial in its native habitat, or in a milder garden, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings or from divisions.
The symbol for a perennial plant, based on
Species Plantarumby Linnaeusis, . [Stearn, William T. "Botanical Latin" (four editions, 1966-92)]
Perennial plants can be short-lived (only a few years) or they can be long-lived, as are some woody plants like trees which can live for over 3,000 years. They can vary in height from only a few millimeters to over 100 meters tall. They include a wide assortment of plant groups from
ferns and liverworts to the highly diverse flowering plants like Orchids and Grasses.
Plants 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.
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 dormancyover cold or dry seasons during the year. 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.Many perennials, in contrast, have specialized to survive under extreme environmental conditions: some have adapted to survive hot and dry conditions, or to survive under cold temperatures. Those plants tend to invest a lot of resource into their adaptations and often do not flower and set seed until after a few years of growth. Many perennials produce relatively large seeds, which can have an advantage, with larger seedlings produced after germinationthat 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 can produce seeds over many years.
In warmer and more favorable
climates, 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 foliagedying back in the winter. These plants are deciduousperennials. 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 evergreenperennials.
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 Arcticwinters, with less sensitivity than trees or shrubs.
Perennial plants dominate many natural
ecosystems 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 prairies and steppes are perennials; they are also dominant on tundratoo cold for tree growth. In forests, perennial plants are of secondary importance to trees and shrubs, but are often still abundant on the forest floor.
Perennial plants are usually better competitors than annual plants, especially under stable, resource-poor conditions. This is due to the development of larger
rootsystems which can access water and soil nutrients deeper in the soil and to earlier emergence in the spring.
Examples of evergreen perennials include "
Begonia" and banana.
Examples of deciduous perennials include
Examples of monocarpic perennials include "
Agave" and some species of " Streptocarpus".
Perennial Tea Ceremony
* [http://extension.oregonstate.edu/mg/botany/cycles.html Plant life cycles]
* [http://www.usna.usda.gov/Hardzone/ushzmap.html USDA Plant Hardiness Zone Map]
* [http://www.urbanext.uiuc.edu/perennials/ Gardening with Perennials]
* [http://www.oznet.ksu.edu/library/hort2/mf2772.pdf Prairie Bloom Perennial Flowers, Kansas State University ] (
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