I wish I had a dollar for every time I had to explain to a student the difference between clovers and wood sorrels. Having leaves with three equal blades does not make a plant a clover.
We usually refer to wood sorrel as Oxalis, it’s genus name. Both clovers and Oxalis have three leaflets per leaf. Both frequently wind up in our nursery pots, but that’s where the comparison ends.
Clovers are members of the pea family and have ball-shaped clusters of tiny flowers on their flower stalks. Oxalis flowers are larger, single and have five identical petals. Flowers are usually yellow, but they can be pink or white. Fruits look like miniature okra pods and are filled with dozens of seeds. A single plant could produce hundreds of seeds.
Oxalis leaves are heart-shaped and have a smooth edge. Clover leaves have a toothed edge and are not heart-shaped.
There are over 500 species of Oxalis. Most are adapted to shady places and don’t invade sunny areas as much. Most species are perennial, and they tolerate a wide range of soil types.
In general, this plant doesn’t grow well in wet soils. When conditions are dry for long periods, wood sorrels go dormant. However, they don’t die and will resume growth when favorable conditions return. This makes them very adaptable.
Wild wood sorrels are a nuisance in lawns, flowerbeds, vegetable gardens and greenhouses. They are more difficult to control than clovers with herbicides.
Most types have either aggressive spreading rhizomes or bulblets. This makes them difficult to restrain because they have different ways to reproduce. Pre-emergent chemicals will keep seeds from growing, but they have little or no effect on rhizomes or bulblets. Using only post-emergent herbicides opens areas up to new plants growing from seeds where soil is exposed.
Cultivated versions have been developed recently. They are often used in flowerbeds and hanging baskets. Vigor, color and the ability to handle adverse conditions are assets. Keeping them from invading places where they aren’t wanted can be a problem.
I have a pink perennial type that has invaded my lawn. It has large leaf blades and a high percentage of 4-leaved plants. It almost looks like it has been planted there. For this reason, I have not declared war on it. It’s pretty and is only conspicuous in spring.
With a name like Oxalis, one might expect plants to be high in oxalic acid. They are. Leaves are edible and have a sour taste which is pleasing to many people. Foliage can be consumed directly or made into an herbal tea. Drying the leaves and grinding them into a powder makes tasty seasoning for grilled foods. It’s a great lemon substitute.
Since plants are high in oxalic acid they might pose a problem if eaten in any quantity by people who have trouble with kidney stones. Other than that, this weed has positive nutritive properties. Leaves are high in vitamins A and C. The only other drawback might be pesticide residue. Never collect from areas that might have been sprayed.
Ted Manzer teaches agriculture at Northeastern High School.
Oh my! I only find this topic to be funny because this morning, an associate referred to clover as ‘trilium’, and for some reason, I repeated the mistake, and we actually conversed about it for quite a while before we realized what we were talking about. It made sense to us at the time, but what a boo boo!
It’s an honest mistake. Trilium vs Trifolium. They look nothing alike though.
Native triliums are actually abundant (or as abundant as they get) in the surrounding forest.