Erigeron is a plant genus that is part of the Asteraceae family. It contains about 390 species of annuals, biennials, and perennials that are found in temperate regions throughout the world. The plants in this genus vary in size and form, but a majority of the species produce daisy-like flowers. Gardeners use plants within the Erigeron genus for rock gardens and borders. Most of the species are susceptible to fungal diseases, such as leaf spot and southern blight.
The genus name is derived from the Greek words eri and geron which translate to "early" and "old man," respectively. The plants of the Erigeron genus are commonly referred to as fleabane. For example, Erigeron karvinskianus is commonly known as the Mexican fleabane, and Erigeron annuus is referred to as the eastern daisy fleabane. This genus was given the descriptive term fleabane because of the belief that the dried flowers of the plant would repel fleas from an infested house.
Plants in this genus have different root systems. For example, E. karvinskianus utilizes a rhizome, which is a horizontal stem that projects roots underground. E. radicatus has a taproot, which is a vertical root that grows straight down into the ground. It is a centralized root from which other roots extend laterally. E. glabellus has a fibrous-root system, in which hundreds of thread-like roots extend from the stem of the plant.
Most species in this genus require well-draining soil to grow well. They can thrive in different types of soil including loamy and sandy. The pH of the soil can vary as well, since most plants in the Erigeron genus can tolerate both acidic and alkaline conditions.
Generally, the area in which the plant is planted should be exposed to direct sunlight. Most plants in this genus can tolerate partial shade. If possible, the plants should be in an area that is somewhat sheltered from the wind.
The appeal of this genus is the daisy-like flowers. E. karvinskianus blooms with white or yellow flowers from late spring to early fall. An assortment of colored petals also prop up during the flowering period. It isn't uncommon to see dark pink or red petals as well.
E. karvinskianus typically has a spread of 3 feet (1 m) and reaches a height of 12 inches (30 cm). The foliage is green throughout the year. It covers the ground like a mat.
Like other species in this genus, E. karvinskianus seeds freely. It usually grows unhindered in the gaps and crevices of pavements. When propagating, it is recommended to sow seeds in a pot during the early spring, and transplant outdoors in late spring.