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Sapphire Lobelia is a charming annual flower that brings classic elegance to summer gardens with its delicate, half-inch sapphire and violet blooms. This Lobelia erinus cultivar thrives in hardiness zones 4-9 and reaches a compact 4-9 inches tall, making it an excellent choice for window boxes, hanging baskets, and garden edges. From seed to flower takes just 70-79 days, rewarding quick growers with abundant blooms that shine brightest in full sun and well-draining soil with a pH between 6.0 and 7.0.
Full Sun
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4-9
9in H x ?in W
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Moderate
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Sapphire Lobelia delivers one of summer's most dependable flowering displays, producing cascading sprays of tiny sapphire-violet blooms that look equally stunning trailing from a hanging basket or edging a garden bed. The compact, bushy growth habit reaches just 4-9 inches tall, so it won't overwhelm tight spaces, and the open-pollinated seeds grow vigorously when started indoors 8-10 weeks before your final frost. Gardeners love it for brightening shaded porches and window sills where many other sun-lovers struggle.
Sapphire Lobelia is grown primarily as an ornamental flower for containers, hanging baskets, window boxes, and garden borders. Its cascading, trailing growth habit makes it especially popular for softening the edges of raised beds and accenting the base of taller plants. The delicate blooms add continuous color to shaded patios and entry gardens throughout the summer months.
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Start Sapphire Lobelia seeds indoors 8-10 weeks before your final spring frost. Scatter seeds on the soil surface or press them lightly into seed-starting mix, as they need light to germinate. Keep soil consistently moist and maintain temperatures between 65-75°F. Seedlings will emerge in 7-14 days and are ready to transplant to larger containers once they develop their first true leaves.
Harden off seedlings gradually over 7-10 days by exposing them to increasing periods of outdoor sun and wind. Transplant outdoors after your final frost date when soil temperatures are consistently above 50°F. Space plants 6 inches apart, with rows 18 inches apart if planting in garden beds. Water thoroughly after transplanting and keep soil moist during the establishment period.
Pinch back young seedlings when they develop 2-3 sets of true leaves to encourage bushier, more compact growth. Deadhead spent flowers regularly throughout the season to stimulate continuous blooming and maintain a tidy appearance. Light cutting back of leggy growth will promote fuller, more floriferous plants.
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