Plantains

Blackseed plantain, Plantago rugelii Dcne.

Broadleaf plantain, Plantago major L.

Buckhorn plantain, Plantago lanceolata L.

Images above: Left: Blackseed plantain rosette (Scott Morris, Cornell University). Right: Red base of the leaf stems of blackseed plantain (Scott Morris, Cornell University).

Images above: Left: Broadleaf plantain seedlings (Joseph DiTomaso, University of California, Davis). Right: Broadleaf plantain rosette (Antonio DiTommaso, Cornell University). 

Images above: Left: Broadleaf plantain (left) and blackseed plantain (right) leaves (Scott Morris, Cornell University). Right: Broadleaf plantain (top) and blackseed plantain (bottom) spikes (Scott Morris, Cornell University).

Images above: Upper left: Buckhorn plantain seedling (Jack Clark, University of California). Upper right: Buckhorn plantain flower (Scott Morris, Cornell University). Bottom: Buckhorn plantain rosette (Scott Morris, Cornell University).

 

Identification

Other common names:

  • Blackseed plantain:  black-seeded plantain, pale plantain, purple-stemmed plantain, red-stalked plantain, Rugel's plantain
  • Broadleaf plantain: common plantain, dooryard plantain, Englishman's foot, greater plantain, greater ribwort, rat-tail plantain, ripplegrass, round-leafed plantain, soldier's herb, waybread, white-man's foot
  • Buckhorn plantain:  black-jacks, English plantain, lamb's tongue, narrowleaf plantain, narrow-leaved plantain, ribgrass, ribleaf, ribwort plantain

Family:  plantain family, Plantaginaceae

Habit:  Perennial herbs with a basal rosette and a leafless flowering stalk. 

Description:  Seedlings form alternate-leaved rosettes.  True leaves have 3-5 prominent, parallel veins.

  • Blackseed plantain:  Cotyledons are spatula shaped, 3-veined, and up to 0.4” (1 cm) long and 0.08” (0.2 cm) wide.  Young leaves are long-stalked, dull green, oval to egg-shaped, and sparsely hairy.  Leaf stalks have upturned edges and are usually pale pink to purplish red at the base.
  • Broadleaf plantain:  Cotyledons are spatula shaped, 0.06-0.28” (0.15-0.7 cm) long by 0.02-0.04” (0.3-0.1 cm) wide, and 3-veined.  Young leaves are long-stalked, oval to egg-shaped, and sparsely hairy.  Leaf stalks have upturned edges and are green or occasionally pinkish at the base.
  • Buckhorn plantain:  Cotyledons are grass-like, 0.67-1.4” (1.7-3.6 cm) long by 0.04-0.06” (0.1-0.15 cm) wide, hairless, without a stalk, and tapered at the base.  The first true leaves are long, narrow and hairy along the margins; later leaves are sparsely hairy, with denser hairs at the base. 

Mature plants form a rosette.  Roots are fibrous with a short taproot.

  • Blackseed plantain:  Leaves are 0.8-8.7” (2-22 cm) long by 0.5-5.6” (1.3-14 cm) wide, oval to egg-shaped, pale green, hairless, and tapered at the tip.  The leaves have 5-9 veins.  Leaf stalks are generally as long as the leaves and are usually pink to purplish red at the base.  Leaf edges are wavy and smooth to occasionally toothed.
  • Broadleaf plantain:  Leaves are 0.8-8” (2-20 cm) long by 0.4-4” (1-10 cm) wide, oval to egg shaped, pale to dull green, leathery, and sparsely hairy.  The leaves have 3-7 veins.  Leaf stalks are generally as long as the leaves and are green or occasionally pink at the base.  Leaf edges are wavy and smooth to occasionally toothed.
  • Buckhorn plantain:  Leaves are lance-shaped, 3.1-12” (8-30 cm) long by 0.4-1.6” (1-4 cm) wide, and 3-7 veined.  The leaves have silky, white to brownish hairs at the leaf base and are otherwise hairless to sparsely hairy.  Leaf stalks are short and inconspicuous or absent.  Leaf edges are generally smooth but may have scattered, small teeth.

Inflorescences, produced at the end of upright and leafless stalks, are spikes of clustered, inconspicuous, flowers.

  • Blackseed plantain:  Plants produce from 1-9 flower stalks which can reach up to 20” (50 cm) tall.  Flower spikes are cylindrical, up to 12” (30 cm) long and 0.23” (0.6 cm) wide, and are composed of up to 300 or more flowers.  The flowers are pale green to whitish and 0.08-0.12” (0.2-0.3 cm) wide.  Flowers are replaced by cylindrical, 0.16-0.24” (0.3-0.6 cm) long capsules which split below the middle to release 4-9 dark brown, glossy, 0.06- 0.08” (0.15-0.2 cm) long seeds.  The seed surface is smooth.
  • Broadleaf plantain:  Plants produce from 1-30 flower stalks which can reach up to 20” (50 cm) tall.  The cylindrical flower spikes are up to 10” (25 cm) long and 0.24” (0.6 cm) wide.  Each spike is composed of up to 400 or more pale green to whitish, 0.08-0.11” (0.2-0.28 cm) wide flowers.  Seeds are produced in oval, 0.16-0.2” (0.4-0.5 cm) long capsules which turn from green to brown as they mature.  Ripe capsules split horizontally at the middle to release 6-30, irregular, glossy, brown, 0.02-0.06” (0.05-0.15 cm) long seeds.  The seed surface has a fine, web-like pattern visible under magnification.
  • Buckhorn plantain:  Plants produce from 1-30 flower stalks, which are up to 18” (45 cm) tall.  The flower spike is conical to cylindrical and 0.8-3.2” (2-8 cm) long by 0.16-0.24” (0.4-0.5 cm) wide.  Individual flowers are 0.08-0.12” (0.2-0.3 cm) wide and brown to yellow-brown.  The stamens protrude from the flowers on up to 0.16” (0.4 cm) long stalks.  Seeds are produced in brown, oval, 0.12-0.16” (0.3-0.4 cm) long capsules.  Each capsule contains 1-2 oblong, glossy, dark brown to black, 0.08” (0.2 cm) long seeds.

Similar species:  Hoary plantain (Plantago media L.) is hairier and has much shorter leaf stalks than broadleaf plantain or blackseed plantain; the leaves are hairier and wider than those of buckhorn plantain, 0.6-4.3” (1.5-11 cm).  Bracted plantain (Plantago aristata Michx.) has narrow leaves similar to buckhorn plantain, however the leaves and flowering stalks of bracted plantain are much hairier than those of buckhorn plantain and the flowering spikes have long, up to 0.8” (2 cm), hairy bracts throughout.  Paleseed plantain (Plantago virginica L.) leaves and stalks are densely covered in soft, wooly hairs unlike broadleaf, blackseed, or buckhorn plantain.

Management

These species are primarily weeds of forages, pastures, and lawns (Chepil 1946, Dale et al. 1965).  Generally, broadleaf plantain inhabits more highly disturbed habitats, has a shorter life span, earlier flowering, produces more and smaller seeds, and functions more like an annual plant than the other species.  Blackseed and buckhorn plantain inhabit less disturbed sites, have a longer life span and lower investment in seed production, and behave more as perennials (Hawthorn 1974, Hawthorn and Cavers 1976, Miao and Bazzaz 1990).  Buckhorn plantain thrives in hay meadows and is particularly common in those with red clover (Cavers et al. 1980).  Except in seed production fields, this is scarcely a problem since the species is sufficiently productive and nutritious to have warranted development as a forage crop, with several commercially available named varieties (Sanderson and Elwinger 2000).  Buckhorn plantain is less common in pastures, but it is a useful component of a mixed species pasture because it continues to produce during hot, dry periods when productivity of C3 grasses and legumes declines (Sanderson and Elwinger 2000).  Broadleaf and blackseed plantain thrive in overgrazed pastures (Bond et al. 2007), but tend to be out-competed in vigorous hay meadows (Hawthorn 1974).  Using an intensive rotational grazing system helps suppress broadleaf and blackseed plantain in pastures by shading the plants during the growth phase of the forage and forcing a more upright growth form that is easier for livestock to eat.  Fertility and good soil aeration will favor forage grasses and legumes relative to plantains.  Sowing un-contaminated forage seed is critical for preventing outbreaks of all three species.

Although broadleaf and blackseed plantain are commonly found in grain and vegetable crops, they rarely compete significantly with crops due to their relatively slow development and prostrate growth habit (Chepil 1946).  Dense populations usually indicate soil problems.  Shallowly moldboard plow with complete inversion (skim plow) to bury large plants, but then adopt a reduced tillage regimen with cover crops to improve soil structure.  Avoid rotary tillage.  Use a tine weeder to regularly harrow out seedlings, and rotate into crops that allow hilling up to cover seedlings in the row.

Ecology

Origin and distribution:  Blackseed plantain is native to the eastern half of the U.S.A and southern Canada.  Broadleaf and buckhorn plantain are natives of Europe that have been spread widely throughout the world, including isolated oceanic islands.  They tend to be uncommon in the lowland tropics.  In North America, they occur throughout the U.S.A.  In Canada, broadleaf plantain occurs northward to above the Arctic Circle, whereas buckhorn plantain occurs primarily in southeastern and southwestern Canada (Hawthorn 1974, Cavers et al. 1980).

Seed weight:  Blackseed plantain, 0.35-0.58 mg (Hawthorn 1974), 0.57-0.70 mg (Miao and Bazzaz 1990), 0.70 mg (Stevens 1932); broadleaf plantain, 0.06-0.29 mg (Hawthorn 1974), 0.17-0.28 mg (Miao and Bazzaz 1990), 0.17-0.34 mg (Sagar and Harper 1964), 0.20 mg (Stevens 1932); buckhorn plantain 0.8-1.5 mg (Primack and Antonovics 1981), 1.0-2.9 mg (Sagar and Harper 1964), 1.2-1.8 mg (Cavers et al. 1980, Schmitt et al. 1992), 1.5-2.2 mg (Sanderson and Elwinger 2000), 1.6-1.9 mg (Sagar and Harper 1961).

Dormancy and germination:  Usually, a substantial proportion of fresh seeds of all three species are capable of immediate germination, though most seeds of broadleaf plantain produced in midsummer are dormant (Cavers et al. 1980, Hawthorn 1974).  Dormant seeds loose dormancy over the winter (Bond et al. 2007).  Optimal temperature for germination of broadleaf plantain is 77-86 °F (25-30 °C), however, exposure to cold (39 °F or 4 °C) for several weeks lowers the minimum temperature required for an optimum response to 59 °F (15 °C) (Pons et al. 1986).  Buckhorn plantain has a similar response to temperature, but the minimum temperatures giving maximum germination are lower than those of broadleaf plantain (Hu et al. 2018, Pons and van der Toorn 1988, Sagar and Harper 1964).  Nitrate stimulates germination of broadleaf (Pons 1986) and buckhorn plantain (Pons 1986, Steinbauer and Grigsby 1957), and fluctuating temperatures promote germination of both of these plantains (Bond et al. 2007, Hu et al. 2018, Pons 1986).  Light promotes germination of all three species, but there can be complex interactions between light, temperature and nitrate.  For example, dormancy of broadleaf and blackseed plantain was relieved by prechilling at 41 °F (5 °C) for two weeks in combination with light, nitrate and alternating day/night temperatures of 86/68 °F (30/20 °C), whereas either light or nitrate was sufficient for germination of buckhorn plantain (Steinbauer and Grigsby 1957).   Cold stratification and fluctuating temperature partially relieved the light requirement of broadleaf plantain (Pons 1986).  Germination of cold-stratified buckhorn plantain seeds was minimally increased by light (Pons and van der Toorn 1988) or by light that passed through a leaf canopy (Pons and van der Toorn 1988, Wulff et al. 1994). 

Seed longevity:  In an experiment that compared all three species, blackseed, broadleaf, and buckhorn plantain survived 21, 30, and 16 years, respectively (Toole and Brown 1946).  Broadleaf plantain can remain viable in soil for 50-60 years (Sagar and Harper 1964).  In one experiment, 68-87% of seeds of broadleaf were viable after 3 years (Chepil 1946) and, in other experiments, seeds maintained up to 10% viability after 40 years of burial in undisturbed soil (Bond et al. 2007, Hawthorn 1974, Kivilaan and Bandurski 1981, Sagar and Harper 1964). Buckhorn plantain seeds had 34-76% viability after 3-4 years (Cavers et al. 1980) and 8% viability after 10 years of burial (Sagar and Harper 1964).  In various experiments in cultivated soil, broadleaf plantain seeds declined by 33-43% per year and buckhorn plantain seeds declined by 60-67% per year (Froud-Williams et al. 1984, Popay et al. 1994).

Season of emergence:  Emergence from mature plants occurs in mid-spring, whereas emergence of seedlings occurs throughout the growing season, with a peak in late spring (Chepil 1946, Hawthorn 1974, Hawthorn and Cavers 1976).  On average, buckhorn emerged earlier than broadleaf plantain, probably because it has a lower temperature minimum for germination (Pons and van der Toorn 1988).

Emergence depth:  Broadleaf plantain seedlings emerge only from the top 0.2” (0.5 cm) of soil (Bond et al. 2007, Froud-Williams et al. 1984).  Buckhorn plantain emerges best from the top 0.8” (2 cm) of soil, with declining emergence to 2.4” (6 cm) (Benvenuti et al. 2001, Sanderson and Elwinger 2000).  No seedlings emerge from 3.1” (8 cm).  Information on emergence depth is unavailable for blackseed plantain, but the small seeds of this species probably restrict emergence to the top 1” (2.5 cm) or less of the soil.

Photosynthetic pathway:  C3.

Sensitivity to frost:  All three species are highly frost tolerant (Stevens 1924).  Even in northern areas they often overwinter as rosettes of small leaves, though in open sites, leaves may be lost for the winter (Sagar and Harper 1964).

Drought tolerance:  Buckhorn plantain is relatively drought tolerant and commonly occurs in droughty sites like the gravel of railroad embankments (Cavers et al. 1980).  Blackseed plantain is probably the least drought tolerant of the three species, with broadleaf plantain having intermediate drought tolerance.  Mature plants of all three species have dense, deep root systems to 32” (80 cm), which allow them to extract soil moisture during drought (Cavers et al. 1980, Hawthorn 1974).

Mycorrhiza:  Broadleaf and buckhorn plantain are mycorrhizal (Harley and Harley 1987, Pendleton and Smith 1983, Veresoglou 2011).   All three plantain species were highly colonized in prairie habitats (Dhillion and Friese 1994).                                                  

Response to fertility:  Broadleaf responds more to increased nutrient levels than does blackseed plantain (Miao and Bazzaz 1990).  But, increased nutrient levels delayed flowering of blackseed more than that of broadleaf plantain (Miao and Bazzaz 1990).  Broadleaf plantain commonly occurs in cracks in concrete pavement (Fagot et al. 2011), indicating that it tolerates very high pH (> 8.0) and low N and P.  Broadleaf and buckhorn plantain were associated with fields with a pH of 6.5 to 7.8 (Dale et al. 1965).  Buckhorn plantain growth, reproductive output and seed weight were increased by increased nutrient availability (Primack and Antonovics 1981, Wulff et al. 1994).  Buckhorn plantain responds to P but tolerates low levels of K (Hoveland et al. 1976).  Buckhorn is more responsive to P than broadleaf plantain (Cavers et al. 1980).  It prefers neutral to calcareous soils and is excluded from soil with a pH below 4.5 (Buchanan et al. 1975, Cavers et al. 1980).  Unlike most non-legumes, buckhorn plantain has bacteria associated with its roots that fix substantial amounts of N (Cavers et al. 1980, Smith and Patriquin 1978). 

Soil physical requirements:  All three species regularly occur on a wide range of soil types from clay to sand.  Buckhorn plantain is most common on dry soils.  All three species are highly tolerant of soil compaction.  Broadleaf plantain tolerates long periods of waterlogging. (Cavers et al. 1980, Hawthorn 1974, Sagar and Harper 1964).  The presence of buckhorn plantain on seashores and the abundance of both buckhorn and broadleaf plantain along roadways receiving de-icing salts indicates that both species are salt tolerant.

Response to shade:  All three species tolerate some shading, but blackseed and buckhorn appear to be more shade tolerant than broadleaf plantain (Cavers et al. 1980, Hawthorn 1974).  Buckhorn plantain seedlings can grow moderately well at light levels similar to those in a dense grassland (Cavers et al. 1980, Fenner 1978), whereas broadleaf and blackseed require periodic mowing or grazing of taller vegetation (Hawthorn 1974).  In shaded conditions, buckhorn plantain leaves become longer and more vertical and seed weight is increased (Cavers et al. 1980, Schmitt et al. 1992).

Sensitivity to disturbance:  Since the stem lies just below ground and the leaves are fibrous and resistant to tearing, these species are highly tolerant of traffic by people, animals and tires (Fagot et al. 2011, Hawthorn 1974, Sagar and Harper 1964).  Even the flowering stalks are flexible and difficult to crush.  Because of its upright habit, buckhorn plantain is somewhat less tolerant of traffic than the other two species (Cavers et al. 1980).  None of the species can grow back out of the soil when completely buried by tillage, but the extensive fibrous root systems of larger plants help them survive and re-root after cultivation.  Consequently, shallow cultivation or hoeing that cuts the plant off just below the stem will be more effective than deeper cultivation that leaves more roots attached.  Removal of buckhorn plantain cotyledons results in reduced early plant growth but no adverse effect on reproduction (Hanley 2012).

Time from emergence to reproduction:  Without competition, broadleaf plantain can flower within 6-10 weeks of emergence (Sagar and Harper 1964).  Blackseed plantain is slower (Miao and Bazzaz 1990).  Development of both species is slowed by competition and cool temperatures, and consequently, many plants remain vegetative their first season when shaded by taller plants. Older plants begin flowering in mid-June and continue flowering through fall (Hawthorn 1974).  Seeds develop 2-3 weeks after the flowers open (Bond et al. 2007, Hawthorn 1974, Sagar and Harper 1964).  Time to flowering in buckhorn plantain varies greatly with conditions and populations (Cavers et al. 1980, Hanley 2012, Primack and Antonovics 1982).  A 13-hour day length is required to initiate flowering in broadleaf and blackseed (Hawthorn 1974) whereas a 16-hour day length is required to induce flowering in buckhorn plantain (Cavers et al. 1980, Sagar and Harper 1964).

Pollination:  These species are wind pollinated.  Some plants of buckhorn plantain produce only flowers of one sex, thereby insuring cross pollination (Cavers et al. 1980).  Other plants of buckhorn, and all plants of broadleaf and blackseed plantain are self-compatible (Bond et al. 2007, Cavers et al. 1980, Hawthorn 1974, Sagar and Harper 1964).

Reproduction:  In a pasture in Ontario, broadleaf and blackseed plantain plants produced an average of 565 and 662 seeds/year (Hawthorn 1974).  In favorable conditions, blackseed plantain can produce 5,000 seeds per plant (Stevens 1932), and broadleaf plantain can produce 15,000 to 36,000 seeds per plant, depending on location (Bond et al. 2007, Salisbury 1978, Sagar and Harper 1964, Stevens 1932).  Seeds of broadleaf and blackseed plantain often remain in the capsules through the winter (Bond et al. 2007, Hawthorn 1974, Sagar and Harper 1964).  In a dry grassland in Ontario, buckhorn plantain plants produced an average of 127 seeds in one season whereas in a nearby fertile agricultural field, plants produced > 10,000 seeds (Cavers et al. 1980).  In Great Britain, buckhorn produced 4,000 seeds per plant (Salisbury 1978).  All three species occasionally produce side shoots that eventually become independent plants (Hawthorn 1974), but this is common only in buckhorn plantain (Cavers et al. 1980).  In all three species, the daughter plants usually remain closely clumped with the parent.

Dispersal:  All three species spread in forage seed (Bond et al. 2007), and buckhorn plantain, in particular, is a notorious contaminant of red clover seed.  Seeds of all three species also spread in soil clinging to tires and machinery (Hodkinson and Thompson 1997).  Buckhorn and broadleaf plantain are spread in livestock manure (Colbach et al. 2013, Kuiters and Huiskes 2010, Mt. Pleasant and Schlather 1994, Cosyns et al. 2005), and blackseed plantain may be as well.  They also spread in bird and deer droppings (Myers et al. 2004).  Seeds of these species contain a mucilage that makes them sticky when wet, and may facilitate dispersal on fur and feathers (Hawthorn 1974).  (Cavers et al. 1980, Bond et al. 2007)

Common natural enemies:  Many fungi and insects attack plantains but substantial damage by natural enemies is rare (Cavers et al. 1980, Hawthorn 1974, Sagar and Harper 1964).

Palatability:  All three species are palatable to livestock (Cavers et al. 1980, Sagar and Harper 1964, Sanderson and Elwinger 2000).  Protein content of buckhorn plantain is similar to and digestibility is often greater than that of a fescue/legume forage in Missouri (Bunton et al. 2020).  Domesticated cultivars of buckhorn plantain have been developed (Sanderson and Elwinger 2000).  Young leaves of broadleaf plantain have been cooked like spinach and dried leaves brewed as tea (Bond et al. 2007).

Notes:  All three species produce large amounts of windborne pollen that can cause hay fever in sensitive individuals (Cavers et al. 1980, Hawthorn 1974).

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