Lobelia Growing Guide

Lobelia erinus


Crop Rotation Group



Fertile, well-drained soil, or use containers.


Full sun to partial shade.

Frost tolerant

Limited. Lobelia can take cool weather but is easily damaged by frost.


Mix a standard application of a balanced organic fertilizer into the soil prior to planting. In midsummer, drench plants with a liquid plant food to stimulate new growth.


Lobelia varieties that bloom blue are wonderful cascading flowers to combine with petunias or other easy annuals in containers. You also can use lobelia to edge beds because of its small size.


Single Plants: 5" (15cm) each way (minimum)
Rows: 5" (15cm) with 5" (15cm) row gap (minimum)

Sow and Plant

Sow tiny lobelia seeds indoors, on top of moist seed starting mix, and provide very bright light. Most gardeners buy lobelia seedlings, which are widely available as bedding plants in spring.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.


Lobelia is a great cool-season flower for adding vivid blue to the garden. Some varieties bloom white or pink.


In early summer, pinch back plants to stimulate the growth of new blossom-bearing branches.


High heat can cause lobelia to suffer, but the plants stay in bloom for many weeks in climates with cool nights.

Planting and Harvesting Calendar

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Pests which Affect Lobelia