Gloxinia is a spectacle when its rich, velvety, deep blue flowers are in bloom. The Gloxinia lofos grows as a vine and can add 3 to 5 feet in length annually. Lofos refers to its botanical name, Lophospermum erubescens. A native of Mexico, it is a perennial in tropical climates but can be grown as an annual elsewhere. Gloxinia most often is seen in hanging baskets, but it can be trained across a wall or up a trellis. Gloxinia lofos is hardy only in U.S. Department of Agriculture zones 8 to 10 and will require indoor overwintering in a heated greenhouse elsewhere.
Plant Gloxinia in a sunny location that has midday shading and good drainage, and after all danger of frost has passed. Usually this will be May or June. Dig 5 to 7 inches of compost into the planting site to enrich the soil and contribute to good drainage. Position the plant against a wall or near a trellis to give it something to climb on.
Fertilise Gloxinia weekly with a liquid balanced fertiliser dissolved in the irrigation water, per label instructions. Apply the fertiliser just before and during blooming. Suspend supplemental food when the plant is no longer producing flowers. Cease fertilising in August in colder zones to prevent the formation of tender September growth, which may be damaged by cooler temperatures.
Water only when the top 3 or 4 inches of soil are dry. Gloxinia is remarkably drought tolerant when it is established. Never allow the soil to get soggy. Cut the watering in half in winter as the plant goes into a semidormant period.
Prune or pinch off the growing tip back to a bud node to encourage a bushy appearance. Terminal ends should be removed when the plant reaches 4 inches tall. Continue the practice monthly during the growing season.
Assist the plant's climb where necessary with plant ties. It is essential to good air circulation to keep the plant vertical and open. Gloxinia lofos sometimes contracts the fungal disease boytris, which can be prevented by air flow and no overhead irrigation.