Perennial
In botany, a perennial plant or simply perennial is a plant that lives more than two years.[1] 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 (secondary growth in girth) from trees and shrubs, which are also technically perennials.[2] 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.[3]
Perennials—especially small
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 subshrubs, which retain a vestigial woody structure in winter, e.g. Penstemon.
The symbol for a perennial plant, based on
Life cycle and structure
Perennial plants can be short-lived (only a few years) or long-lived. They include a wide assortment of plant groups from non-flowering plants like
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, turions, woody stems, or crowns which allows them to survive periods of dormancy over cold or dry seasons; these structures typically store carbohydrates which are used once the dormancy period is over and new growth begins.[10] In climates that are warm all year long, perennials may grow continuously.[11] Annuals which complete their life cycle in one growing season, in contrast with perennials, produce seeds as the next generation and die;[12] 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.[13] 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.[14] Some perennials are semi-deciduous, meaning they lose some of their leaves in either winter or summer.[15] 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.[16]
Some perennial plants are protected from
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 biennials 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.[18]
Perennial species may produce relatively large seeds that have the advantage of generating larger seedlings that can better compete with other plants. Perennials also produce seeds over many years.
An important aspect of cold acclimation is overexpression of
Cultivation
Perennials that are cultivated include: woody plants like
Each type of plant must be separated differently; for example, plants with fibrous root systems like daylilies, Siberian iris, 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 rhizomes; 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.[25] In the United States more than 900 million dollars worth of potted herbaceous perennial plants were sold in 2019.[26]
Benefits in agriculture
Although most of humanity is fed by the re-sowing of the seeds of
Location
Perennial plants dominate many natural
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.[31]
Types
- Herbaceous - plants that have foliage and stems that die to the ground at the end of the growing season and which show only primary growth. Examples include frost-tender plants such as Cochliasanthus caracalla.
- Evergreen - plants that have persistent foliage without woody stems. Examples include many Senecios, Begonia, Gaillardias, Dimorphothecas, Gazanias, Thunbergias, Dietes, Osteospermums, Tradescantias and Vincas, among others.
- Woody - plants with persistent above ground stems that survive from one growing season to the next, with primary and secondary growth, or growth in width protected by an outer cortex. Some may be
- Monocarpic - plants that flower, set seeds once and then die. Examples include, Agave and some species of Streptocarpus
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.[33] Some examples include;
Perennial fruits
The majority of fruit bearing plants are perennial even in temperate climates.[34] Examples include
- Apple
- Blackcurrant
- Blueberry
- Blackberry
- Currant
- Grape
- Pear
- Plum
- Raspberries
- Strawberry
Perennial herbs
Many herbs are perennial,[35][36] including these examples:
Perennial vegetables
Many vegetable plants can grow as perennials in tropical climates, but die in cold weather.[37] Examples of some of the more completely perennial vegetables are:
- Asparagus
- Chives
- Globe artichoke
- Jerusalem artichoke
- Kale
- Leek
- New Zealand spinach
- Rhubarb
- Sea kale
- Sweet potato
Aquatic plants
Many aquatic plants are perennial even though many do not have woody tissue. Examples include
- Crassula helmsii - New Zealand Stonecrop
- Pontederia cordata - Pickerell weed
- Stratiotes aloides - Water Soldier which sinks to the bottom of the pond in winter
- Utricularia vulgaris - Common bladderwort which produces turions as its overwintering stage
See also
- Annual plant – Plant which completes its life cycle within one growing season and then dies
- Biennial plant – Flowering plant that takes two years to complete its biological life cycle
- Herbaceous plant – Plant that has no persistent woody stem above ground
- Herbchronology
- Perennial grain – Grain crops that remain productive for two or more years without replanting
- Lilium nanum
- Lilium papilliferum
Notes
- environmental weeds in some areas. They may be invasive in regions where are they are not native because their ability for rapid spread chokes out native plant species and alters habitats. For Vinca, areas affected include parts of Australia, New Zealand, Canada, and the United States, especially coastal California.[21][22][23]
References
- ^ The Garden Helper. The Difference Between Annual Plants and Perennial Plants in the Garden. Retrieved on 2008-06-22.
- ISBN 978-1405332965.
- S2CID 260332117.
- ^ "Perennial Plants: Roots of Immortality". Wisconsin Pollinators. Retrieved 2023-11-18.
- ^ Stearn, William T. "Botanical Latin" (four editions, 1966-92)
- ISBN 978-1-108-49985-9. p. 77–.
- ISBN 978-1-135-32307-3. p. 175–.
- ISBN 978-1-4381-0941-1. p. 132–.
- ISBN 978-3-319-26944-3. p. 315–.
- ISBN 978-1-4496-5000-1.
- ISBN 978-0-393-73203-0. p. 87–.
- ISBN 978-1-4200-4925-1.
- ISBN 978-1-905839-40-7. p. 153–.
- ISBN 978-1-60469-707-0. p. 134–.
- ^ "Annuals, Biennials, Perennials: What's the Difference?". ANR Blogs. Retrieved 2021-02-08.
- ISBN 978-0-323-14560-2. p. 88–.
- ^ 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.
- PMID 17416545.
- ^ a b 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. doi: 10.1002/ajb2.1584. Epub 2020 Dec 19. PMID: 33340368
- ISBN 978-0-7167-1742-3p. 44
- ^ Cal-IPC (2017-03-20). "Vinca major Profile". California Invasive Plant Council. Retrieved 17 June 2021.
- ISBN 978-1-920932-71-8. Retrieved 17 June 2021.
- ^ Hawaiian Ecosystems at Risk project (HEAR). "Vinca major information from the Global Compendium of Weeds (GCW)". www.hear.org. Retrieved 17 June 2021.
- ^ Janick 1986, p. 51.
- ^ "Dividing Perennials". extension.psu.edu. Retrieved 2018-10-29.
- ^ "Table 7. Potted Herbaceous Perennial Plants Sold: 2019" (PDF). www.nass.usda.gov.
- ^ Glover et al. Future Farming: A return to roots? Retrieved on 2008-11-11.
- ^ Moffat 1996 [1] Retrieved on 2008-11-14
- ^ Cox et al. 2000 [2] Retrieved on 2008-11-14
- S2CID 259200859.
- ^ Stephen B. Monsen. Proceedings--ecology and Management of Annual Rangelands. United States Department of Agriculture, Forest Service, Intermountain Research Station; 1994. p. 342–.
- ISBN 978-0-7603-6874-9. p. 18–.
- ^ "20 of the best perennials". BBC Gardeners World Magazine. Retrieved 18 November 2023.
- ^ Nuffstetler, Erin. "Edible Perennials That Will Bear Year After Year". The Spruce. Retrieved 18 November 2023.
- ^ Waddington, Elizabeth (14 May 2020). "35 Perennial Herbs To Plant Once & Enjoy For Years". Rural Sprout. Retrieved 18 November 2023.
- ^ Waddington, Elizabeth (17 May 2021). "20 Perennial Herbs That Return Each Year | Horticulture.co.uk". Horticulture Magazine. Retrieved 18 November 2023.
- ^ "Perennial veg to grow". BBC Gardeners World Magazine. Retrieved 18 November 2023.
External links
- USDA Plant Hardiness Zone Map (archived 4 July 2012)
- Gardening with Perennials
- Edible Aroids
- Plants for a Future