What Is Lobelia Erinus?

Lobelia erinus, sometimes called edging lobelia or trailing lobelia, is a species of ornamental flowering perennial that is a native of southern Africa but has become commonplace in several U.S. states. Although this plant is perennial in warmer climates, it is grown like an annual in areas that are colder. It is hardy to USDA zones 10 and 11. Lobelia erinus produces flowers that are usually violet-blue with a white middle, but cultivars are available that produce red, pink, white, light blue, or purple blooms. Gardeners often use the upright species of lobelia for edging a garden bed, but the varieties known as trailing lobelia do best in containers, hanging baskets, or window boxes.

A member of the bellflower family Campanulaceae, lobelia erinus tends to grow to about 6 inches (15 cm) high and can spread up to 1 foot (30 cm). Its leaves can be dark or medium green. In some cases, the leaves could develop a burgundy or bronze tinge, depending on the amount of sunlight received. This plant produces a very small fruit containing the seeds for propagation. Some of the cultivars of lobelia erinus include Rosamond, Crystal Palace, Fountain Series, Blue Moon, Sapphire, and Cascade.

Lobelia erinus has no significant problems with disease or insects. It produces flowers during spring and summer in most locales. The blooms are said to attract butterflies. Lobelia erinus will cease to bloom when summer temperatures rise too high. If the plants are cut back at this time, they are likely to bloom one more time when temperatures drop in autumn.

Some gardeners find lobelia erinus difficult to start from seed. If buying young plants in the spring, choose stocky specimens that are not wilted and show no indication of disease. It is best to select plants that have not flowered yet, because they will be capable of greater root development. Seedlings should be planted about a week before the last spring frost in a sunny location that receives a small period of shade during the day. Lobelia erinus thrives on rich, moist soil with the aid of organic matter such as compost.

To create fuller foliage and profuse blooms, it is helpful to pinch off the lobelia's ends. Lobelia will die quickly without sufficient watering, so it is vital to keep the soil moist throughout the growing season. When used as an annual, these plants should be discarded after the first substantial autumn frost.

Lobelia erinus, commonly known as edging lobelia or garden lobelia, is a flowering plant native to South Africa. It's renowned for its vibrant blue, violet, purple, or white flowers that add a splash of color to gardens and landscapes. This annual or perennial herb is a popular choice for borders, containers, and hanging baskets due to its cascading growth habit.

Caring for Lobelia erinus involves ensuring it's planted in well-draining soil with regular watering, though it's important to avoid waterlogging. It thrives in full sun to partial shade and benefits from occasional fertilization. Deadheading spent blooms can promote further flowering. In hotter climates, providing afternoon shade can help prevent the plant from wilting.

Historically, different species of Lobelia have been used for medicinal purposes, but Lobelia erinus is primarily grown for ornamental use. Some Lobelia species contain lobeline, a compound once used in smoking cessation treatments. However, it's important to note that many Lobelia plants can be toxic if ingested in large quantities, so they should be used medicinally with caution and under professional guidance.

Lobelia erinus can be either an annual or a perennial, depending on the climate. In cooler regions, it is typically grown as an annual because it cannot survive frost. However, in milder climates with warmer winters, Lobelia erinus can behave as a perennial, returning year after year to grace gardens with its delicate blooms.

Lobelia erinus can be susceptible to pests such as aphids and whiteflies, which can be managed with insecticidal soaps or neem oil. Diseases like powdery mildew and root rot can also affect the plant, particularly in humid conditions or when there is poor soil drainage. Proper air circulation and avoiding overhead watering can help prevent these issues.

Lobelia erinus contributes to garden biodiversity by attracting pollinators such as bees, butterflies, and hummingbirds, which are drawn to its nectar-rich flowers. By supporting these pollinators, Lobelia erinus plays a role in maintaining the health of the local ecosystem and ensuring the pollination of surrounding plants, thus enhancing overall biodiversity.