White clover (Trifolium repens) is a perennial herb, one of the most cultivated species of clover. It can be found on lawns and grasslands all over the world. White clover is often cultivated as a forage plant and used for green manure in agriculture.
I. Appearance and Characteristics
Trifolium repens (from Latin repens, meaning crawling), the white clover, is a herbaceous perennial plant in the bean family Fabaceae (otherwise known as Leguminosae).
It is native in Europe and Central Asia, ubiquitous throughout the British Isles, introduced in North America, South Africa, Australia, New Zealand, Japan and elsewhere, and globally cultivated as a forage crop.
White clover has been used as a model organism for global research into ecology and urban evolution. As part of the Global Urban Evolution Project (GLUE) scientists from 26 countries examined the production of cyanide by over 110,000 clover plants from 160 cities. Cyanide can be useful to clover plants as a deterrent to herbivores. Analyzing urban-rural differences, scientists found that cyanide production tended to increase with distance from the center of cities, suggesting that clover populations were adapting to factors commonly found in urban centers worldwide. Possible factors could include temperature (freezing is related to cyanide content), herbivory pressures, and drought stress. As clover habitats, the downtowns of cities may more closely resemble other far-flung cities than nearby rural areas.
The species includes varieties often classed as small, intermediate and large, according to height, which reflects petiole length. The term ‘white clover’ is applied to the species in general, ‘Dutch clover’ is often applied to intermediate varieties (but sometimes to smaller varieties), and ‘ladino clover’ is applied to large varieties.
It is a herbaceous, perennial plant. It is low growing, with flowering heads of whitish florets, often with a tinge of pink or cream that may come on with the aging of the plant. The heads are generally 1.5–2 centimeters (1⁄2–3⁄4 in) wide, and are at the end of 7 centimeters (2+3⁄4 in) peduncles or inflorescence stalks. The flowers are mostly visited by bumblebees and often by honey bees.
The leaves are trifoliolate, smooth, elliptic to egg-shaped and long-petioled and usually with light or dark markings. The stems function as stolons, so white clover often forms mats, with the stems creeping as much as 18 cm (7 in) a year, and rooting at the nodes. The leaves form the symbol known as shamrock. Almost always, a white clover will be trifoliolate. However, one can, but only sometimes, possess four or more leaflets.
The plant may be slightly toxic to dogs. Moreover, some varieties of wild white clover plant may be slightly toxic to humans.
II. How to Grow and Care
You will find that white clover does not require much care at all. Put it in a spot with slightly acidic soil and good drainage, throw in a bit of shade, and do not let the soil dry out completely. This basic care should be enough for the plant to thrive.
But, because Trifolium repens does spread aggressively, it may move into areas of your yard where you do not want it. Pulling it out will require extra landscape maintenance. So think carefully before you plant white clover unless you do not mind having it take over. At the very least, do not install it near flower beds.
Sunlight
White clover performs best in partial sun, but it tolerates being planted in areas that receive full sun.
Watering
White clover performs best in evenly moist soil. It tolerates dry ground but will not spread as much. This can actually be a good thing if you are concerned about the plant spreading out of control.
Soil
The most important soil requirement for Trifolium repens is good drainage.
Fertilizing
This highly useful ground cover is a nitrogen-fixer and therefore does not need to be fertilized. This saves you time, effort, and money. Take this fact into account if you are landscaping on a budget. White clover is also a popular crop for overwintering in the vegetable garden. Planted in the fall and tilled under in the spring before vegetables are planted, the clover adds nitrogen needed by your edible plants and also crowds out some of the undesirable garden weeds.
Pruning
Propagation
White clover, like other clovers, spreads out by sending offshoots from a plant that will develop another plant. These offshoots can be separated from the “mother” plant. Here’s how:
- Locate a mature plant that has an offshoot branched out from it.
- Using pruning shears or scissors, cut the offshoot to separate it from the mother plant.
- Plant the offshoot slightly below the soil in the desired location and secure the plant by pushing the soil down around it. Then water.
How to Grow from Seed
This plant grows easily from seed. It is best to do this in spring or summer during warm weather. Directly sow the seeds in your yard by raking the soil and then simply scattering them around and watering. The clover will start sprouting in as little as two to three days, but can take up to seven to 10 days depending on the temperature. Keep the area watered and moist where the seeds have been spread.
Pests and Diseases
The plant is aggressive in growth and considered by many a weed, especially for those who wish to eradicate their lawns. The plant is prone to attack by pests and diseases. Clover root weevil is identified as the most dangerous pest. This pest feeds on leaves and nitrogen-fixing nodules. This reduces the nitrogen-fixing capabilities and the general vigour of the plant.
The plant may also be inflicted with diseases from viruses and bacteria. An example is the Alfalfa mosaic virus (AMV), which leads to yellow streaks parallel to leaf veins, distorting leaves and stunted plant growth. To tackle this, plant varieties resistant to this should be used. Root rot infection may occur where some roots are in tan to red colouration and the seedlings are infected. Maintaining soil and optimum soil pH can help protect the plant from disease.
III. Types of White Clover
In addition to the wild plant, improved varieties of Trifolium repens include:
- Micro clover: this is shorter, with smaller leaves
- ‘Atropurpureum’: sports chocolate-brown foliage with green margins
- ‘Dragon’s Blood’: maybe the most attractive variety of white clover, bearing tricolored leaves (green, red, and white)
IV. Uses and Benefits
Forage management
White clover has been described as the most important forage legume of the temperate zones. Symbiotic nitrogen fixation (up to 545 kilograms per hectare per year (486 lb/acre/a) of N, although usually much less, e.g. about 110 to 170 kilograms per hectare per year (98 to 152 lb/acre/a)) in root nodules of white clover obviates synthetic nitrogen fertilizer use for maintaining productivity on much temperate zone pasture land. White clover is commonly grown in mixtures with forage grasses, e.g. perennial ryegrass (Lolium perenne).
Such mixtures can not only optimize livestock production, but can also reduce the bloat risk to livestock that can be associated with excessive white clover in pastures. Such mixtures also tend to avoid issues that could otherwise be associated with cyanogenic glycosides (linamarin and lotaustralin) intake on pure or nearly pure stands of some white clover varieties. However, problems do not inevitably arise with grazing on monocultures of white clover, and superior ruminant production is sometimes achieved on white clover monocultures managed to optimize sward height.
Companion planting, green manure, and cover crops
White clover serves as an excellent mulch over any other legume. The plant helps in creation of lush walkways and build soil. It outperforms other weeds as it is easy to manage and produce nitrogen. Some of the benefits include:
- White clover stands produce 80 to 130 pounds per acre, which is less than average legume.
- It has thick and an interconnected root system, which breaks up and prevents soil compaction.
- The plant is known to be the most resilient varieties of the Clover genus. Thus, it is also widely used as a ground cover crop. It withstands mowing much effectively.
- The extensive root system and ground cover of white clover helps prevent soil erosion. Hence, the nutrients remain intact. Owing to prevention of erosion and nitrogen fixation, it helps boost soil health.
- White clover provides an excellent weed cover. The plant has large root system and biomass production of the plant, and competes well in extreme conditions.
Culinary uses
Besides making an excellent forage crop for livestock, its leaves and flowers are a valuable survival food: they are high in proteins, and are widespread and abundant. The fresh plants have been used for centuries as additives to salads and other meals consisting of leafy vegetables. They are not easy for humans to digest raw, but this is easily fixed by boiling the harvested plants for 5–10 minutes. Native Americans ate some species raw. Dried white clover flowers may also be smoked as a herbal alternative to tobacco.
Medicinal uses
In India, T. repens is considered a folk medicine against intestinal helminthic worms, and an experimental in-vivo study validated that the aerial shoots of T. repens bear significant anticestodal (anti-tapeworm) properties.
