An Introduction To White Clover

One of the most common lawn weeds in North America, perhaps second only to dandelions would be White Clover. This is a conspicuous weed that really stands out in a manicured lawn, but will be absent in taller grasslands and prairies. In less-maintained lawns, it can look fine blending with other weeds. But I would wager that just about anyone who pays attention to grass has seen these little globular white flowerheads poking above the grass. Well, let’s have a deeper look into what white clover is, what it is used for (yes, really), how it interacts with our ecosystems & greater environment.

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What is White Clover

White Clover is a low-growing legume native to Europe, and introduced to nearly all of North America^[1]. Scientifically known as Trifolium repens, it grows four to six inches tall in full sun to part-shade and clay to sandy-loam soil textures. Blooming globular 1/2″ flowerheads from May to October, it attracts numerous pollinators and even hosts some caterpillars^[2][3].

It’s small patches of tri-folate leaves^[4] arising, then sprawling amongst the blades of turfgrass give way to tine white flowerheads that generally poke just above the lawn itself. This can be the bane of a meticulous lawncare person, but as I stated above it does have some benefits in that the flowers DO provide nectar to bees.

Seeing that white clover does provide benefits to pollinators, it’s mere presence in a lawn increases the ecological value of that space compared to turfgrass alone. And although it isn’t one of our natives that can survive in a mowed lawn, it is better to have this one among the blades of grass.

Why is White Clover so prolific in lawns?

White Clover is highly adaptable for growing conditions, giving it the ability to grow in most turf-grass conditions except severe drought, which will prevent it’s growth or induce dormancy. However, the drought won’t kill it, it will just make it dormant until sufficient moisture comes back. But aside from that, White Clover will grow best in thin lawns that are less cared for, and there are several key factors why this happens.

First, it has been shown that clover will grow better in the absence of nutrients in the soil^[6]. This is significant since it is a legume it can fix nitrogen to the soil, effectively making it’s own fertilizer. Lawns that are well cared for often have several applications of fertilizer a year, which would reduce the white clovers need to fix nitrogen, and thus spend more energy on flowering.

Second, it is a low growing plant. It won’t grow well if it is being shaded by taller plants like what would happen naturally in a prairie or deep forest. Thus, your short turfgrass keeps competition at bay.

And third, lawns that are less cared for have more bare spots or areas that clover can colonize. And since it will colonize via seed and stolon (above ground runner that forms new plants), it creep into new areas and set roots before you know it. But a thick healthy lawn will not offer much ‘open space’. You’ve heard the saying “nature abhors a vacuum”? Well, clover is all too happy to fill that vacuum!

Facts

• Native to Europe, it has been introduced to North America where it is present in all 50 of the United States and most of Canada
• The entire plant is edible for humans and mammals alike
• A legume, it fixes nitrogen to the soil
  • Up to 45% of that nitrogen is stored in the roots, making it an excellent cover crop^[5]
• It is low growing, and thus can survive repeated mowings

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Present Range

As shown below, White Clover can be found in almost all of the United States and Canada. It is truly a prolific plant that spreads on it’s own, but also through it’s use as a cover crop and as forage for livestock.

How white clover got to America

Reference Table

Scientific Name	Trifolium repens
Common Name(s)	White Clover, Dutch Clover
Native Range, USDA Zone	Europe. USDA Hardiness zones 3-10
Bloom Time	Spring-Fall
Bloom Duration, Color	White
Height	4-6″
Spacing / Spread	6″
Light Requirements	Full sun to part-shade
Soil Types	Sandy loam to clay. Does well in compacted soils
Moisture	Moist to medium-moist
Fauna Associations / Larval Hosts	Bees visit flowers. Hosts the cloudy sulphur butterfly

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Pros and Cons

Believe it or not clover can bring some benefits over regular turf grass, but also some drawbacks. I will explain these below:

Pro

Cover crop

White Clover is a legume, which means it has the ability to take nitrogen from the air and store it in it’s roots (known as nitrogen fixing). Thus it can be a popular choice for a cover crop that can naturally add fertility and organic matter to soils.

Forage / grazing

This plant is edible to pretty much all mammals (even humans). But it is quite popular with livestock, rabbits, and deer.

Pollinators

The flowers of White Clover will produce nectar, and this is very attractive to bees, smaller butterflies, and other pollinators. When I’m mowing my lawn I often have to pause to let a pollinator leave the white flowers before my mower passes over them.

Tough

White clover can take a lot of physical abuse. It survives foot traffic as good as any plant, so you can see it growing and persisting in soccer fields nationwide.

Erosion control

White clover germinates and grows fairly quickly, but it’s creeping stems will put down roots as they expand from the center. These adventitious roots, as they are known, plus the creeping foliage are what make this plant a good choice for erosion control.

Cons

Weedy & Invasive

White Clover will profusely self seed in low-growing environments or lawns. There is a reason that there are so many herbicides dedicated to killing it. This plant can take hold and be tough to get rid of.

Tough

Yes, being tough is both a pro and a con for white clover! The ability to survive so much foot traffic is a pro, but it also makes it a con if you wish to get rid of it!

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Identification

Not sure if you have white clover? Well, let’s break down just the key characteristics.

Stems

Small, round, glabrous stems creep along the ground forming clumps. The stems (for the main and stolons) are small, only 2-4 mm diameter (~1/8″).

Leaves

The leaves are palmately trifoliate and attached to stems that are up to 2-1/2″ long. Individual leaflets are 1/2″-1-1/2″ diameter and obovate or obcordate in shape. The margins will be denticulate, although this is tough to notice without looking closely. And the leaves may or may not have white chevron markings on the upper surface^[4].

Flowers

For inflorescence, globular flowerheads that are 1/2″-3/4″ diameter on erect stems (penduncles). Each flowerhead will contain 20-40 flowers that are white or white-pink and tubular^[4].

Roots

The plant will form a central taproot that is thin, but stout. Adventitious roots will form along the stolons, which creep along the ground^[4].

Look-alike – Yellow Sorrel

One common lawn weed that also looks a lot like white clover, at least the leaves do is Yellow Sorrel. See below for an image.

You can clearly see the leaves resemble white clover, at a glance anyway. But these leaves (apart from being a different shape) will also fold up at night. Now, once the flower starts blooming the difference will be obvious. But prior to that, when only the leaves are shown it is possible to confuse the two species at a quick glance.

Growing conditions

For growing conditions, White Clover will prefer full sun and moist to medium moist soils. It is not drought tolerant, and will become dormant during extreme droughts of a hot summer.

When it comes to soil textures, it does best in clay to silt, and does poorly in sandy soils. But – if the soil is heavily compacted it may thrive (think of lawns).

But this is a cool season plant, and will go dormant in winter only to reemerge in Spring.

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Wildlife associations

Pollinators

The flowers are frequently visited by numerous species of bee including bumblebees, mason bees, and honey bees. You will also see smaller butterflies such as skippers and moths pollinating the flowers.

Besides nectar, there are quite a few insects that will feed on this plant as either larval stage or various beetles and grasshoppers.

Birds

Various birds will eat the seed seed during winter, such as sparrows. While larger birds like turkey, grouse, and partridge will eat the foliage and seedheads.

Wild mammals

Both deer and rabbits enjoy foraging clover. Rabbits in particular really seem to favorite white clover for food. But ground squirrel, groundhogs, voles, and even bear have been known to eat the foliage.

Livestock

This is a good grazing plant and as such is often recommended by USDA. But cattle, goats, horses and sheep can all eat this plant as forage.

Control

If one wishes to control white clover, such as in a lawn, then there are numerous over-the-counter herbicides one can use. Any broadleaf weed control will work, and most of these can be purchased ready-to-use or as a concentrate.

The key factor is that the tiny leaves of white clover can make it hard to get the herbicide to stick. Large droplets will just roll off the leaf, rendering your efforts useless. So, if you have a pump-sprayer you can use for poisons, then set it to the finest mist that you can. Spray when the outdoor temperatures are less than 85F, and on a calm day. These herbicides are taken up by the plant via the leaves, so it can be good to do this several days before one wishes to mow their lawn.

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Red Clover vs White Clover

Unlike it’s cousin Red Clover, white clover is low growing and can survive repeated mowings. Also differing from it’s aforementioned cousin it will bloom while low to the ground, while Red Clover more often doesn’t bloom until it is a bit taller. But both will have globular flowerheads, however red clover will be pink-red while white clover is, well, white. The leaflet size of red clover is also much larger than that of white clover. Also, the leaflet shape of red clover is generally a more elongated ovate shape.

Uses

Erosion control

The creeping nature of White Clover combined with the adventitious roots it’s creeping stems put down mean that White Clover can effectively stop erosion. The leaves and foliage will reduce the force of the rain, and the roots will help hold the soil.

Forage

Many farmers and ranchers add white clover to their hayfields for use as forage for livestock. It is a cheap, tough plant that is vigorous and can withstand grazing.

Cover Crop

The ability of White Clover to take nitrogen from the air and store it in it’s roots make it an excellent choice of cover crop. It is an effective method to get nitrogen and organic matter into the soil.

Native American uses

Despite not being native to North America, White Clover spread fast enough so that some tribes developed their own medicinal uses. Several used infusions of the whole plant or flowers to treat fevers and colds, while others used it to treat liver spots^[7].

Conclusion

Look, I’m no fan of invasive species and often write guides on how to kill them. But when it comes to invaders, this one does provide some real benefits to our ecosystem. Many animals will feed on it (you can eat it too), pollinators like the nectar from it’s flowers, and it does host at least one caterpillar. So, in the grand scheme of things, when it comes to my yard/property, White Clover is pretty low on my list for invasive species that I’m trying to eliminate. I prefer to attack more destructive invasive species with virtually no benefit and a lot of negatives like Japanese Stiltgrass, Bush Honeysuckle, and Oriental Bittersweet. Those really, really displace natives creating an ecological wasteland.