Sowing & Growing

For successful germination, it’s important not to bury Lobelia seeds as they require light to sprout. Instead, scatter them evenly across the surface of lightly moistened potting mix and gently press them into the soil. Be patient, as germination may take up to three weeks. Once leaves appear on the young plants, they can be carefully separated into individual cells or small plant pots.

When it’s time to plant, “harden off” your transplants by gradually introducing them to outdoor conditions once warm spring days arrive. However, bring them back inside until a few weeks after all risk of frost has passed. After this period, you can confidently transplant them into your garden, a suitable container, or a hanging pot. Lobelia plants prefer full sun but can tolerate some partial shade. They are not picky about soil as long as it is reasonably well-drained, distinguishing them from the native L. cardinalis, which favors wet soils.

Trailing varieties of Lobelia work beautifully in rock gardens or cascading over the sides of planters, while some cultivars are labeled as “edging lobelia,” featuring a more upright growth habit. Trailing and edging varieties can be combined in the same spaces for a fuller appearance. As for maintenance, trailing lobelia is relatively low-maintenance. Although spent blossoms will naturally drop, deadheading can encourage more abundant blooming. Pruning in mid-summer can stimulate new growth and enhance the late-summer blossom display, especially in warmer zones. Water moderately but frequently, keeping the soil consistently moist. Biweekly feeding with a high-phosphorous liquid fertilizer throughout the blooming cycle promotes more lavish blooms.

Lobelia is resilient against diseases and pests, with deer showing minimal interest. Spider mites, if present, can be controlled by periodic spraying with insecticidal soaps. In damp conditions, watch for fungal infections on leaves or stems, and promptly remove and destroy infected plants while adjusting your watering schedule accordingly. Cultivate Lobelia with minimal effort and enjoy the abundant and vibrant blossoms it brings to your garden.