Much maligned plant is the figwort, I have part of the front garden full of different varieties and the wild species, they make a stunning spring show, a very early ground cover, gone by the end of summer and are easy to dig up as they are very shallow rooted. They don't interrupt bulbs or perennials from growing through them and can be almost completely covered by larger plants at little detriment to them for months on end, yet provide a short green carpet at a time when there is little else poking it's head through the soil.
The leaves range from bright and dark green with black, brown and silver patterns to rival Cyclamen leaves, flowers most often yellow but may also be orange and white/cream in single and fully double forms. Smashing little plants, at least here in England even though lots of gardeners hate them.
Bluebells and Wood Anemones are just as vigourous, all three grow together in large woodland carpets here and yet these former two are beloved plants. Never understood the persecution myself.
Ranunculus ficaria, Lesser Celandine is from Europe and has no controls here. Where it gets in woodlands it out competes our Bluebells, Wood Anemones and our other native woodland plants, producing a monoculture over many acres. Some official verbage:
The University of Maine Cooperative Extension (2004) states that:
"R. ficaria is primarily a threat to native plants and native plant diversity in lowland woods and on flood plains. It out competes native plants through its extremely early seasonal growth and the development of a dense network of roots and tubers in the soil. Over time it forms extensive carpets in natural areas, crowding out native plants, especially native ephemeral (short-lived) wildflowers. The survival strategy of native ephemeral wildflowers is to grow and flower early in the spring before leaf-out of the forest canopy. By doing so, these plants receive needed sunlight and can take advantage of nutrients released from decaying material over the winter. R. ficaria uses the same strategy, but starts growing earlier in the season and is far more aggressive in its use of space. Unfortunately, R. ficaria is still available commercially for garden plantings."
From Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service
“Lesser celandine is currently found in 20 northeastern states and in Oregon, Washington and several Canadian provinces. It occurs most commonly on moist, forested floodplains areas. The greatest impact of lesser celandine is on native spring-flowering plants. Lesser celandine emerges in advance of most native spring species, giving it a great competitive advantage. Once established, it spreads rapidly across the forest floor to form a blanket of leaves which native species are unable to penetrate”.
WOW, that's so strange... I just signed on to identify this plant myself, growing at the bottom of our hill by the road. Very pretty yellow flowers, but I was hoping for something to add to my "pretty native stuff" area. Darn!