Product Code Database
In horticulture, the term perennial ( + , "through the year") is used to differentiate a plant from shorter-lived annual plantThe Garden Helper. The Difference Between Annual Plants and Perennial Plants in the Garden. Retrieved on 2008-06-22. and biennial plant. It has thus been defined as a plant that lives more than 2 years. (1993). 9780863189791, Dorling Kindersley. ISBN 9780863189791 |name=RHS The term is also loosely used to distinguish plants with little or no woody growth (secondary growth in girth) from trees and shrubs, which are also technically perennials. (2025). 9781405332965, Dorling Kindersley. ISBN 9781405332965 Notably, it is estimated that 94% of plant species fall under the category of perennials, underscoring the prevalence of plants with lifespans exceeding two years in the botanical world.
Perennials (especially small ) that grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their rootstock or other overwintering structure, are known as Herbaceous plant perennials. However, depending on the rigours of the local climate (temperature, moisture, organic content in the soil, microorganisms), a plant that is a perennial in its native habitat, 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 their above-ground biomass does not survive the winter.
There is also a class of evergreen perennials which lack woody stems, such as Bergenia which retain a mantle of leaves throughout the year. An intermediate class of plants is known as , which retain a vestigial woody structure in winter, e.g. Penstemon.
The symbol for a perennial plant, based on Species Plantarum by Carl Linnaeus, is , which is also the astronomical symbol for the planet Jupiter.Stearn, William T. "Botanical Latin" (four editions, 1966-92)
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 , , woody crowns, , turions, woody stems, or crowns which allows them to survive periods of dormancy over cold or dry seasons; these structures typically store which are used once the dormancy period is over and new growth begins. In that are warm all year long, perennials may grow continuously.Lynden B. Miller. Parks, Plants, and People: Beautifying the Urban Landscape. Norton; 2009. . p. 87–. Annual plant which complete their life cycle in one growing season, in contrast with perennials, produce seeds as the next generation and die; the seeds may survive cold or dry periods or germinate soon after dispersal depending on the climate.
Some perennials retain their foliage year-round; these are evergreen perennials. Deciduous perennials shed all their leaves part of the year. Forests And Forest Plants - Volume III. EOLSS Publications; 24 February 2009. . p. 153–. Deciduous perennials include herbaceous and woody plants; herbaceous plants have stems that lack hard, fibrous growth, while woody plants have stems with buds that survive above ground during dormancy.Tracy DiSabato-Aust. The Well-Tended Perennial Garden: The Essential Guide to Planting and Pruning Techniques, Third Edition. Timber Press; 22 February 2017. . p. 134–. Some perennials are semi-deciduous, meaning they lose some of their leaves in either winter or summer. Deciduous perennials shed their leaves when growing conditions are no longer suitable for photosynthesis, such as when it is too cold or dry. 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.T.T. Kozlowski. Shedding of Plants Parts. Elsevier; 2 December 2012. . p. 88–.
Some perennial plants are protected from because they have underground roots that produce adventitious shoots, bulbs, crowns, or Underground stem;R. F. Wagle. Fire, Its Effects on Plant Succession and Wildlife in the Southwest: Some Effects of Fire on Plant Succession and Variability in the Southwest from a Wildlife Management Viewpoint. School of Renewable Natural Resources, University of Arizona; 1981. p. 5. other perennials like trees and shrubs may have thick cork layers that protect the stems. Herbaceous perennials from temperate and alpine regions of the world can tolerate the cold during winter.
Perennial plants may remain dormant for long periods and then recommence growth and reproduction when the environment is more suitable, while most annual plants complete their life cycle during one growing period, and Biennial plant have two growing periods.
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 the actual task of growth. For example, most trees regain the ability to grow during winter but do not initiate physical growth until the spring and summer months. The start of dormancy can be seen in perennial plants through withering flowers, loss of leaves on trees, and halting of reproduction in both flowering and budding plants.
Perennial species may produce relatively large seeds that have the advantage of generating larger that can better compete with other plants. Perennials also produce seeds over many years.
An important aspect of cold acclimation is overexpression of DNA repair genes.Jaikumar NS, Dorn KM, Baas D, Wilke B, Kapp C, Snapp SS. Nucleic acid damage and DNA repair are affected by freezing stress in annual wheat (Triticum aestivum) and by plant age and freezing in its perennial relative (Thinopyrum intermedium). Am J Bot. 2020 Dec;107(12):1693-1709. . Epub 2020 Dec 19. PMID 33340368 In Thinopyrum intermedium a perennial relative of common wheat Triticum aestivum, conditions of freezing stress were shown to be associated with large increases in expression of two DNA repair genes (one gene product a photolyase and the other, a protein involved in nucleotide excision repair).
Each type of plant must be separated differently; for example, plants with fibrous root systems like Daylily, Iris sibirica, or grasses can be pried apart with two garden forks inserted back to back, or cut by knives. However, plants such as bearded irises have a root system of Rhizome; these root systems should be planted with the top of the rhizome 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. In the United States more than 900 million dollars worth of potted herbaceous perennial plants were sold in 2019.
Perennial plants are usually better long-term competitors, 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. Annual plants have an advantage in disturbed environments because of their faster growth and reproduction rates.Stephen B. Monsen. Proceedings--ecology and Management of Annual Rangelands. United States Department of Agriculture, Forest Service, Intermountain Research Station; 1994. p. 342–.
Cultivation
Perennials that are cultivated include: woody plants like grown for their edible fruits; shrubs and trees grown as landscaping Ornamental plant; herbaceous food crops like asparagus, rhubarb, Strawberry; and subtropical plants not hardy in colder areas such as , eggplant, and coleus (which are treated as annuals in colder areas). Perennials also include plants grown for their flowering and other ornamental value including bulbs (like Tulip, narcissus, and gladiolus); lawn grass, and other groundcovers, (such as Vinca and dichondra repens).
Benefits in agriculture
Although most of humanity is fed by the re-sowing of the seeds of Annual plant grain crops, (either naturally or by the manual efforts of humans), provide numerous benefits.Glover et al. Future Farming: A return to roots? Retrieved on 2008-11-11. 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 ). These potential benefits of perennials have resulted in new attempts to increase the seed yield of perennial species,Moffat 1996 [12] Retrieved on 2008-11-14 which could result in the creation of new perennial grain crops.Cox et al. 2000 [13] Retrieved on 2008-11-14 Some examples of new perennial crops being developed are perennial rice and intermediate wheatgrass. A perennial rice developed in 2018, was reported in 2023, to have provided a similar yield to replanted annual rice when evaluated over eight consecutive harvests.
Location
Perennial plants dominate many natural 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 and are perennials; they are also dominant on tundra too cold for tree growth. Nearly all forest plants are perennials, including trees and shrubs.
Types
List of perennials
Each section contains a short list of species related to that topic, these are an example as the true lists would fill several books.
Perennial flowers
Perennials grown for their decorative flowers include very many species and types. Some examples include:
Perennial fruits
The majority of fruit bearing plants are perennial even in temperate climates. Examples include:
Perennial herbs
Many are perennial, including these examples:
Perennial vegetables
Many vegetable plants can grow as perennials in tropical climates, but die in cold weather. Examples of some of the more completely perennial vegetables are:
Aquatic plants
Many aquatic plants are perennial even though many do not have woody tissue. Examples include:
See also
Notes
External links
|
|
