Outsidepride Blue Carpet Lobelia Plant Flower Seeds - 5000 Seeds Lobelia blue carpet can grow in hanging baskets, containers, or work as a low growing ground cover. Blue lobelia erinus in an annual flowering plant which will grow in USDA Zones 3 - 9. Lobelia makes a nice ground cover with a compact, trailing growth habit. Masses of blue blooms cover the green foliage. Lobelia is also perfect for edging borders, rock gardens, hanging baskets and window boxes. Sow 3 - 5 seeds per cell or approximately 5000 seeds covers 100 square feet to use as a groundcover plant.