Lobelia excelsa, also known as tupa roja, is an evergreen shrub that belongs in the family Campanulaceae. Native to the mountainous regions of Chile, Lobelia excelsa is cold hardy at 15 to 20 degrees Fahrenheit. Its gray-green foliage and attractive tubular, orange flowers attract both butterflies and hummingbirds. It blooms from late spring through early fall. Lobelia excelsa is a hardy shrub that will do well for novice gardeners or those seeking a low maintenance addition to a butterfly or flower garden.
Plant and grow Lobelia excelsa in an area of your garden that receives full-sun conditions throughout the day. The plant will grow and bloom best if situated in a high-light area. It will not perform well if planted in total shade.
Consider the plant's size at maturity, when selecting a planting site. Space multiple plants 6 to 8 feet apart, as it can grow four to 6 feet tall and have a width of 3 to 5 feet. Give the plants enough space for proper air circulation and so that they do not take over another plant species that are too close.
Grow the lobelia excelsa in a rich soil medium that drains well, for best growth and flowering. Amend sandy or poor soils with peat, compost or manure, working it approximately one foot down into the existing soil. Amend clay or poorly draining soils with compost and sand, to make them richer and improve drainage.
Water newly planted Lobelia excelsa plants two to three times per week for the first three weeks. Water established plants approximately once per week, depending on your local weather conditions. Lobelia excelsa is drought tolerant once it has established itself in the garden. Giving the plant more water will increase its size.
Fertilize Lobelia excelsa in early spring, summer and fall with a 10-10-10, granular fertilizer. Water the fertilizer in well, after applying it. Apply a fresh layer of compost to the top soil, in early spring.
Prune Lobelia excelsa heavily to control its shape and size. Begin trimming in early spring through late summer. Withhold pruning the shrub during late fall and winter, in the event your area suffers a frost or freeze.