A perennial plant or simply perennial is a plant that lives more than two years. Some sources cite perennial plants being plants that live more than three years. The term (per- + -ennial, "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widely used to distinguish plants with little or no woody growth from trees and shrubs, which are also technically perennials.
Perennials, especially small flowering plants, that grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their rootstock, 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. Tomato vines, for example, live several years in their natural tropical/subtropical habitat but are grown as annuals in temperate regions because they don't survive the winter.
There is also a class of evergreen, or non-herbaceous, perennials, including plants like Bergenia which retain a mantle of leaves throughout the year. An intermediate class of plants is known as subshrubs, which retain a vestigial woody structure in winter, e.g. Penstemon. The local climate may dictate whether plants are treated as shrubs or perennials. For instance, many varieties of Fuchsia are shrubs in warm regions, but in colder temperate climates may be cut to the ground every year as a result of winter frosts.
Perennial plants can be short-lived (only a few years) or they can be long-lived, as are some woody plants like trees. They include a wide assortment of plant groups from ferns and liverworts to the highly diverse flowering plants like orchids and grasses.
Perennials typically grow structures that allow them to adapt to living from one year to the next through a form of vegetative reproduction rather than seeding. 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. 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 have developed specialized features that allow them to survive extreme climatic and environmental conditions. Some have adapted to survive hot and dry conditions or 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 germination that can better compete with other plants. Some annuals produce many more seeds per plant in one season, while some (polycarpic) perennials are not under the same pressure to produce large numbers of seeds but can produce seeds over many years.
Dividing perennial plants is something that gardeners do around the months of September and October. The point of doing the division at this time is to allow approximately 6 weeks for adequate root growth prior to the ground reaching a freezing temperature. Due to the leaves falling from trees, as well as the excessive amount of rain received in most places during the fall weeks, the ground has adequate moisture for rapid growth. Each type of plant must be separated differently;for example, plants with large root systems like oriental grasses can be cut by knives and pulled apart. However, plants such as Irises have a root system known as a Rhizomes, these root systems should be planted with the bulb of the plant just above ground level, with leaves from the following year showing. The point of dividing perennials is to increase the amount of a single breed of plant in your garden. The more you divide your perennial plants every year, the more vast your garden will grow.
In warmer and more favorable climates, perennials grow continuously. In seasonal climates, their growth is limited to the growing season.
In some species, perennials retain their foliage all year round; these are evergreen perennials. Other plants are deciduous perennials, 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. In many parts of the world, seasonality is expressed as wet and dry periods rather than warm and cold periods, and deciduous perennials lose their leaves in the dry season.
With their roots protected below ground in the soil layer, perennial plants are notably tolerant of wildfire. Herbaceous perennials are also able to tolerate the extremes of cold in temperate and Arctic winters, with less sensitivity than trees or shrubs.
Perennial plants can also be differentiated from annuals and biennials in that perennials have the ability to remain dormant over long periods of time and then continue growth and reproduction. The meristem of perennial plants communicates with the hormones produced due to environmental situations (i.e. seasons), reproduction, and stage of development to begin and halt the ability to grow or flower. There is also a distinction between the ability to grow and actual task of growth. For example, most trees regain the ability to grow in the midst of winter but do not initiate physical growth until the spring and summer months. The start of dormancy can be seen in perennials plants through withering flowers, loss of leaves on trees, and halting of reproduction in both flowering and budding plants.
The growth of a deciduous perennial plant is studied to the point where we can make basic assumptions. The first assumption is not only about the daily net photosynthetic rate of a plant increasing, but also how it saturates with the size of the plant. Secondly, while the production of the plant is discarded, the stored material will be used during the next season to keep it growing. Finally, the plant maximizes its lifetime by choosing the best growth schedule within each season and also allocating resources between reproduction for the year and the storage for next year. Perennial planting in general have a low storage, low growth rate, and a short growing season. When it comes to the optimal phenology of a plant, its quantity can be measured in two specific ways: firstly, by its productivity, which is the growth rate of the plant and secondly, by its stability, the survival storage it requires to survive through the season.
Although most of humanity is fed by the re-sowing of the seeds of annual grain crops, (either naturally or by the manual efforts of man), perennial crops provide numerous benefits. Perennial plants often have deep, extensive root systems which can hold soil to prevent erosion, capture dissolved nitrogen before it can contaminate ground and surface water, and out-compete weeds (reducing the need for herbicides). These potential benefits of perennials have resulted in new attempts to increase the seed yield of perennial species, which could result in the creation of new perennial grain crops. Some examples of new perennial crops being developed are perennial rice and intermediate wheatgrass. The Land Institute estimates that profitable, productive perennial grain crops will take at least 25 years to achieve.
|Seeds from various perennial flowers|
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. Herbaceous perennial plants 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 tundra too cold for tree growth. Nearly all forest plants are perennials, including the trees and shrubs.
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.
The following perennial plants are used as herbs:
Many vegetable plants can grow as perennials in tropical climates, but die in cold weather. Some of the more completely perennial vegetables are:
Anemone nemorosa is an early-spring flowering plant in the buttercup family Ranunculaceae, native to Europe. Common names include wood anemone, windflower, thimbleweed, and smell fox, an allusion to the musky smell of the leaves. It is a herbaceous perennial plant growing 5–15 centimetres (2–6 in) tall.Anthriscus sylvestris
Anthriscus sylvestris, known as cow parsley, wild chervil, wild beaked parsley, or keck is a herbaceous biennial or short-lived perennial plant in the family Apiaceae (Umbelliferae), genus Anthriscus. It is also sometimes called mother-die (especially in the UK), a name that is also applied to the common hawthorn. It is native to Europe, western Asia and northwestern Africa; in the south of its range in the Mediterranean region, it is limited to higher altitudes. It is related to other diverse members of Apiaceae, such as parsley, carrot, hemlock and hogweed. It is often confused with Daucus carota which is known as Queen Anne's lace or wild carrot, also a member of the Apiaceae.Astragalus propinquus
Astragalus propinquus (syn. Astragalus membranaceus, commonly known as Mongolian milkvetch in English and as huáng qí (Chinese: 黃芪), běi qí (Chinese: 北芪) or huáng huā huáng qí (Chinese: 黃花黃耆), in Chinese, is a flowering plant in the family Fabaceae. It is one of the 50 fundamental herbs used in traditional Chinese medicine. It is a perennial plant and it is not listed as being threatened.Centella asiatica
Centella asiatica, commonly known as centella, Asiatic pennywort or Gotu kola, is a herbaceous, frost-tender perennial plant in the flowering plant family Apiaceae. It is native to the wetlands in Asia. It is used as a culinary vegetable and as a medicinal herb.Cicely
Myrrhis odorata, with common names cicely (), sweet cicely, myrrh, garden myrrh, and sweet chervil, is a herbaceous perennial plant belonging to the celery family Apiaceae. It is one of two accepted species in the genus Myrrhis.Elephant garlic
Elephant garlic (Allium ampeloprasum var. ampeloprasum) is a perennial plant belonging to the onion genus. It is not a true garlic, but actually a variant of the garden leek. It has a tall, solid, flowering stalk and broad, flat leaves much like those of the leek, but forms a bulb consisting of very large, garlic-like cloves. The flavor of these, while not exactly like garlic, is much more similar to garlic than to leeks. The flavor is milder than garlic, and much more palatable to some people than garlic when used raw as in salads. It is sometimes confused with solo garlic.Erigenia
Erigenia bulbosa, also known as harbinger of spring or pepper and salt, is a perennial plant in the carrot family (Apiaceae). E. bulbosa is the only species in the genus Erigenia and tribe Erigenieae. This plant is known as harbinger of spring because it is one of the earliest blooming native wildflowers of rich forests in the mid-latitude United States. Throughout most of its range it blooms from late February through early April.Hypericum adpressum
Hypericum adpressum, common name creeping St. Johnswort, is a flowering perennial plant found growing on wet ground in the United States.Iris illyrica
Iris illyrica, with the common name Illyrian Iris, is a perennial plant from the iris family (Iridaceae), native to Southeastern Europe.Iris pallida
Iris pallida (Dalmatian iris or sweet iris) is a hardy flowering perennial plant of the genus Iris, family Iridaceae. It is native to the Dalmatian coast (Croatia) but widely naturalised elsewhere. It is a member of the subgenus iris, meaning that it is a bearded iris, and grows from a rhizome.Kikyō
Kikyō may refer to:
Platycodon, species of herbaceous flowering perennial plant native to East Asia
Kikyō Station, JR railway station in Hakodate, Hokkaido, JapanLovage
Lovage (), Levisticum officinale, is a tall perennial plant, the sole species in the genus Levisticum in the family Apiaceae, subfamily Apioideae.Lychnis flos-cuculi
Lychnis flos-cuculi, commonly called Ragged-Robin, is a herbaceous perennial plant in the family Caryophyllaceae. This species is native to Europe, where it is found along roads and in wet meadows and pastures. In Britain it has declined in numbers because of modern farming techniques and draining of wet-lands and is no longer common. However, Lychnis flos-cuculi has become naturalized in parts of the northern United States and eastern Canada.Ocimum tenuiflorum
Ocimum tenuiflorum (synonym Ocimum sanctum), commonly known as holy basil, tulasi (sometimes spelled thulasi) or tulsi, is an aromatic perennial plant in the family Lamiaceae. It is native to the Indian subcontinent and widespread as a cultivated plant throughout the Southeast Asian tropics.Tulsi is cultivated for religious and traditional medicine purposes, and for its essential oil. It is widely used as a herbal tea, commonly used in Ayurveda, and has a place within the Vaishnava tradition of Hinduism, in which devotees perform worship involving holy basil plants or leaves.
The variety of Ocimum tenuiflorum used in Thai cuisine is referred to as Thai holy basil (Thai: กะเพรา kaphrao); it is not to be confused with Thai basil, which is a variety of Ocimum basilicum.Panax ginseng
Panax ginseng, the ginseng, also known as Asian ginseng, Chinese ginseng, or Korean ginseng, is a species of plant whose root is the original source of ginseng. It is a perennial plant that grows in the mountains of Eastern Asia.Perovskia atriplicifolia
Perovskia atriplicifolia (), commonly called Russian sage, is a flowering herbaceous perennial plant and subshrub. Although not a member of Salvia, the genus of other plants commonly called sage, it is closely related to them. It has an upright habit, typically reaching 0.5–1.2 m tall (1.6–3.9 ft), with square stems and grey-green leaves that yield a distinctive odor when crushed. It is best known for its flowers. Its flowering season extends from mid-summer to late October, with blue to violet blossoms arranged into showy, branched panicles.
It is native to the steppes and hills of southwestern and central Asia. Successful over a wide range of climate and soil conditions, it has since become popular and widely planted. Several cultivars have been developed, differing primarily in leaf shape and overall height; 'Blue Spire' is the most common. This variation has been widely used in gardens and landscaping. P. atriplicifolia was the Perennial Plant Association's 1995 Plant of the Year, and the 'Blue Spire' cultivar received the Award of Garden Merit from the Royal Horticultural Society.
The species has a long history of use in traditional medicine in its native range, where it is employed as a treatment for a variety of ailments. This has led to the investigation of its phytochemistry. Its flowers can be eaten in salads or crushed for dyemaking, and the plant has been considered for potential use in the phytoremediation of contaminated soil.Sanguisorba officinalis
Sanguisorba officinalis, the great burnet, is a plant in the family Rosaceae, subfamily Rosoideae. It is native throughout the cooler regions of the Northern Hemisphere in Europe, northern Asia, and northern North America.
It is a herbaceous perennial plant growing to 1 m tall, which occurs in grasslands, growing well on grassy banks. It flowers June or July.Sanguisorba officinalis is an important food plant for the European large blue butterflies Maculinea nausithous and M. teleius.Shoot
In botany, shoots consist of stems including their appendages, the leaves and lateral buds, flowering stems and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. In the spring, perennial plant shoots are the new growth that grows from the ground in herbaceous plants or the new stem or flower growth that grows on woody plants.
In everyday speech, shoots are often synonymous with stems. Stems, which are an integral component of shoots, provide an axis for buds, fruits, and leaves.
Young shoots are often eaten by animals because the fibres in the new growth have not yet completed secondary cell wall development, making the young shoots softer and easier to chew and digest. As shoots grow and age, the cells develop secondary cell walls that have a hard and tough structure. Some plants (e.g. bracken) produce toxins that make their shoots inedible or less palatable.
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