Plantain

Plantain is the common name for around 200 plants in the family Plantaginaceae. There are about 20 species in Aotearoa New Zealand, including 10 endemic species. The plantain species often seen in New Zealand lawns and along the roadsides were introduced by early settlers. Interestingly, these species became so widespread around the globe that they are often referred to as Englishman’s foot because they appeared and flourished in areas where Europeans settled!

Plantain is a perennial herb, and various species have been used in traditional medicines for centuries – including traditional Māori medicine. Externally, plantain is useful for insect bites and other skin-related issues. As a food source, plantain is very nutritious – it is high in calcium and vitamins A, C and K. It also works as a diuretic, meaning that it increases the amount of urine excreted.

Plantain structure

Plantain has a coarse (thick) fibrous root system that has both fibrous roots and a tap root. Fibrous roots are branching roots that grow from the stem. A tap root is a central root that grows downwards. The tap root can take up water from deeper in the soil layer and provides a moderate degree of drought tolerance but enables the plant to quickly recover following rain or irrigation.

Plantain is a dicotyledon – its seeds have two embryonic leaves or cotyledons. The crown, or base of the plant, is just below ground level. Leaves grow in a rosette (a circular arrangement) from the crown. Plantain is a flowering plant. The flower stems rise above the leaves, and brown seed heads form at the tip of the stems. Plantain is wind pollinated.

Plantain as a forage crop

Plantain has been a pasture species for a long time. Both the narrow-leaved and broad-leaved plantain species populate paddocks – the same species that are considered weeds in urban lawns. The plants have thicker, deeper roots than common pasture grasses so they tolerate dry summer conditions and provide an alternative feed source.

Agronomists took note of plantain’s ability to provide summer feed and have developed the narrow-leaved species found in pasture and bred varieties that are more functional within pastures. First of all, new cultivars grow upright rather than low to the ground. Flatweeds do better in lawns that are frequently mowed, whereas upright plants can compete with other pasture plants for light, and it’s easier for the animals to graze them.

New plantain cultivars have larger leaves that are more easily digested. The cultivars also have a higher mineral content. Research shows that, when plantain is fresh and soil moisture is adequate, plantain’s feeding value is greater than ryegrass/white clover – traditional pasture forages. It’s also highly palatable to livestock and is selectively grazed before other grasses or legumes. Palatability means that farmers need to carefully manage the paddocks to prevent the animals from overgrazing plantain when it is part of a mixed sward.

Plantain may help reduce nitrogen leaching

A cow consumes up to 100 kg of fresh pasture per day. Pasture plants like clover have lots of nitrogen. Some of the nitrogen is utilised by the cow, but the excess is excreted. A cow produces around 25 L of urine per day, and when a cow urinates, a lot of nitrogen is concentrated into a small area – known as a urine patch. The amount of nitrogen in a urine patch is much higher than the surrounding pasture plants can use, and the excess nitrogen can leach into the soil.

Scientists are investigating whether plantain can reduce leaching. Plantain has some definite benefits – it has a higher water soluble carbohydrate/nitrogen ratio compared to some common forages, has a higher water content and acts as a diuretic, so cows urinate more frequently. This dilutes the nitrogen in urine patches. Scientists think that a diet with 30% plantain is needed to cause a reduction in urinary nitrogen. Learn more about their research in this article.