Lobelia is a family of flowering annual and perennial plants that bloom in the summer and flower in a range of hues from red to deep cobalt blue and purple to crisp white. It is hardy in USDA zones 3 through 9 and has a rounded, mounding growth habit. At maturity, it reaches a maximum of 4 feet in height and 2 feet in spread. It can be used in a variety of garden settings and provides a dramatic boost of color when planted en masse.
Create a blanket of low-growing lobelia flowers in beds and borders or as underplantings for a tree by planting one or more complementary lobelia species en masse roughly 2 to 3 feet apart.
Plant lobelia in patio pots, hanging baskets and wall-mounted planters. As it grows, the fullness of the plant and flowers will spill over the lip of the container and cascade just a bit. To create more of a cascade, plant lobelia right along the lip of the container.
Intersperse lobelia plants between perennials in mixed-border plantings to quickly fill empty spots with color.
Grow lobelia as edging plants arranged in rows along edging stones, pathways, driveways or brick dividers.
Create decorative patterns in large flower beds and borders by using different species of lobelia in geometric patterns such as lattice pattern with borders and lattice lines in one color of lobelia and a second color to fill in the field squares of the lattice pattern. Create curvilinear patterns and drifts of lobelia using two, three or more cultivars.
Plant lobelia in a partial shade exposure in warmer southern climates and in a full sun exposure in cooler northern climes. Water sufficiently to maintain evenly moist soil and amend nutritionally weak soil with compost, aged manure or balanced complete 10-10-10 fertilizer to keep the plants in peak health.