Greater and lesser celandine are not particularly closely related; their shared common name seems based solely on similarly colored flowers. The “greater” variety is also known as the celandine poppy (Chelidonium majus) and, indeed, is a member of the Papaveraceae, or poppy, family. The “lesser” variety is sometimes called figwort (Ranunculus ficaria) and is a member of the Ranunculaceae, or buttercup, family. The species are only distantly related, as both families are part of the order Ranunculales.
Both of these Old World taxa have been introduced to the North America as ornamentals and have escaped into the wild to become invasive species. Lesser celandine is particularly troublesome, as it emerges very early in the spring (late February to March in some areas), before native spring wildflowers and quickly forms continuous carpets of vegetation above the ground and mats of roots and tubers below ground.
Three years ago we received a load of mulch free of charge from the village government. The department of public works collects brush, wood, and bags of weeds from the curb and chips it, creating large steaming piles of mulch down near the sewage treatment plant. Thinking it would be great to have free mulch for our flowerbeds we ordered a load and spread it around the property.
It was apparently full of lesser celandine tubers and the following spring there were large patches of the plant in several locations around the yard. Initially we were charmed by the glossy leaves and bright, cheerful yellow flowers, but the following year we noticed that it had expanded its coverage greatly and began to take steps to rid our nascent meadow garden of this invasive pest.
Lesser celandine is an ephemeral, which is to say that after it finishes flowering the vegetation withers and dies back, coming back the following spring from the roots using energy stored in its tubers. Because it flowers before many bees are active, the plant has an alternative method of spreading, producing bulbils on its stems, which fall to the ground after the plant flowers and sprout to form new plants. It also spreads vegetatively by sprouting new plants from its root mass.
Two methods are recommended to rid your property of this pernicious plant. Small patches should be dug up with a trowel or small shovel, making sure to get all the roots and tubers. Larger infestations can be treated with glyphosphate-based herbicides (e.g., Monsanto’s RoundUp). Because the plant emerges before native plants, the herbicide can be applied to kill it without harming other species in the same area.
Greater celandine is also regarded as an invasive in some areas, but does not seem to be as aggravating as its lesser cousin. Much has been written about this plant in alternative medicine circles because of its reputed curative qualities. Botanists consider all parts of the plants to be generally poisonous, but, as is often the case, herbalists and other medical mavens outside the mainstream consider small doses of the poisonous isoquinoline alkaloids to be beneficial for curing everything from an upset stomach to cancer.
The plant also exudes a yellowish sap or latex when it is broken open. This substance has been traditionally used on small wounds to sterilize and heal them, although handling the plant can cause mild dermatitis.
The common name of both of these species, “celandine,” is derived from the Old English celidoine, which through Old French and medieval Latin, is sourced to the Greek word khelidon or “swallow”. Although there are many species of hirundine bird in Europe, generally only one of them is referred to as a “swallow,” the others being referred to as various types of martin. Hirundo rustica is often called the European swallow, but is a Holarctic species; the same taxon in North America is called the barn swallow. It is the only North American or European species with an actual swallow-tail, which is to say, very deeply forked.
European swallows migrate to sub-Saharan Africa each winter, some of them traveling all the way from the United Kingdom to South Africa. The greater celandine was so-named because it begins to flower when the swallows begin to arrive in southern Europe and stops flowering when they depart in the fall. Its other vernacular name is “swallow-wort,” wort being the general Old English name for “plant”.