Dictionary of Flowers: Lobelia Erinus
(Edging or Trailing Lobelia)

Lobelia Erinus, beautiful purple flowers. Image used under a Creative Commons licence with the kind permission of Chris Gladis and Flickr

Lobelia Erinus, beautiful purple flowers. Image used under a Creative Commons licence with the kind permission of Chris Gladis and Flickr

  • Lobelia Erinus
  • Common name: lobelia, edging lobelia, trailing lobelia
  • Family:  Campanulaceae 
  • Category: frost sensitive perennial in USDA zones 9 to 11, grown as an annual elsewhere
  • Height: 9"
  • Width: 6"
  • Sun/part shade
  • Blooms: late spring to early fall
  • Growth habit: clumping, trailing. Used as a spiller or filler in container combinations
  • Maintenance: easy
  • Soil: fertile, evenly moist, well drained. Water regularly if grown in containers
  • Garden uses: containers, hanging basket, mixed border, groundcover, rock garden
  • Diseases: fungal diseases
  • Pests: thrips, spider mites

Lobelia is usually grown as an annual. It is easily available as plant starts in nurseries during spring and early summer.

Native to South Africa, it bears small deep blue, azure, pink or white flowers on lacy, threadlike stems.

Lobelia performs better in cooler weather. 

It is a garden staple for use in containers and hanging baskets during spring and early summer.

Lobelia grows well in fertile, moist soil with neutral to slightly acid pH. It prefers full sun, but during summer it is best to keep it out of mid-day sun.

It can also be grown in bright shade. Plants suffer in the hottest part of the summer and might need to be severely cut back.

Plants will start blooming again when the weather turns cooler.  Established lobelia can withstand a light frost in early fall. 

Different varieties of lobelia have either a trailing or clumping habit. Keep it in mind when choosing a variety for your containers.

All varieties need to be watered consistently, more so if growing in full sun. They do not require deadheading. 

IWILLWRITECAPTION. Image used under a Creative Commons licence with the kind permission of NAMEOFFLICKRUSER and Flickr

Lobelia can be grown from seed. Start seed indoors in starting mix in late winter or early spring.

Sow thinly and do not cover, as seed needs light to germinate. At 70F, it takes seed about three weeks to germinate.

When seedlings emerge, place in bright light to avoid leggy seedlings and move to a cooler location. Harden off and plant in small clumps in their permanent position in the garden after danger of frost has passed.




IWILLWRITECAPTION. Image used under a Creative Commons licence with the kind permission of NAMEOFFLICKRUSER and Flickr

Lobelia can develop diseases if overwatered. Improve drainage and discard affected plants.

If pests become a problem, spray with insecticidal soap.

Popular varieties:

  • Lobelia erinus 'Regatta' series - trailing variety, blooms can be white, rose pink, light blue, deep blue or variegated blue and white
  • Lobelia erinus 'Rivera' series - mounding variety, early flowering. White, pink, rose, blue and deep blue flowers
  • Lobelia erinus 'Anabel' series - semi-trailing. White, pink, lavender, blue and bicolor blooms
  • Lobelia erinus 'Crystal palace' - dwarf, up to four inches high. Mounding, long blooming period. Deep blue blooms
  • Lobelia erinus 'Fountain' series - trailing. Available in six colors, white, rose, crimson, lilac and blue/ deep blue
  • Lobelia erinus 'Rosamond' - magenta flowers, mounding
  • Lobelia erinus 'Laguna' series - cascading, eight to ten inches long. Flowers can be white, lilac, pale blue and deep blue

IWILLWRITECAPTION. Image used under a Creative Commons licence with the kind permission of NAMEOFFLICKRUSER and Flickr

Full List of Dictionary of Flowers Entries

Annuals For Containers

Perennials For Containers

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