Scrambling upward on a trellis or atop another nearby plant to a height of 5 to 8 feet, the gloriosa lily (Gloriosa superba) is also known as the climbing lily or flame lily. This tropical plant from Africa doesn't survive in cold winter regions, but gardeners often plant the tuber in late spring and store it indoors over winter after fall frost kills the foliage. Gloriosa lily's flowers display twisting, wavy petals containing red, yellow and green hues. Long stamens jet out from each blossom to look like cat whiskers or a scrawny spider. Grow this lily outdoors year-round in U.S. Department of Agriculture Hardiness Zones 8 and warmer.
Dig the garden soil with a shovel where you want to plant and grow the gloriosa lily. Choose a location that receives at least eight hours of sunlight, where the soil never becomes soggy after rains. This plant excels in a porous soil, such as gravel with bits of organic matter and soil. Overturn the soil and break up any clumps to a depth of 12 inches.
Add coarsely textured organic matter to the soil. Place small bark nuggets, compost, manure or peat atop the soil, in a layer 3 to 6 inches deep and incorporate it with the shovel to a depth of 12 inches. Add gravel or grit to the soil to make it drain better, especially if the native soil is clay. Sandy soils benefit from additional organic material to improve the soil fertility.
Plant the tuber horizontally in a planting hole that is 3 to 4 inches deep. If you live in USDA Hardiness Zones 4 through 7, plant after there is no danger of frost in spring and the soil temperatures warm to above 21.1 degrees Celsius.
Water the planted tuber freely once the green stems and leaves appear from the soil and the temperatures warm above 26.7 degrees Celsius. Keep the soil moist, but never overwater or create muddy conditions.
Apply a 3-inch layer of compost atop the soil around the gloriosa lily to act as a source of nutrients and to prevent weeds. Maintain this mulch layer across the entire growing season. Don't pile mulch against the stems; keep it at least 3 inches away from the stems to prevent fungal diseases.
Fertilise the gloriosa lily with a well-balanced (10-10-10) liquid fertiliser solution according to product label directions in spring and summer. Continue to fertilise as part of watering the soil as long as temperatures remain warm and flowers exist, up until frost occurs. Stop feeding in mid-autumn in USDA Zones 9 and warmer.
Insert a trellis or other structure for the stems of the gloriosa lily to climb. The trellis or plant stakes need to be at least 4 feet tall. In areas with long growing seasons, the trellis should be at least 6 feet tall.
Dig up the tuber with a shovel within one week of the fall frost in USDA Zones 4 through 7. Brush off soil from the tuber and allow it to air-dry in a cool, dry and shaded location. Place the tuber in a box or crate with dry coarse sawdust or shredded newspaper and store it in a cool, dry place where the temperature remains between 7.22 and 15.5 degrees C over the winter storage period. Do not put in the refrigerator.
Fill a large container, at least 2 gallons in volume, with a gritty potting mix that contains organic matter like peat or compost. Gloriosa lily needs good drainage, so choose a container with a hole in the bottom.
Plant the lily tuber about 3 to 4 inches deep. Lay it on its side in the planting hole. Tamp the soil down gently over the tuber and water the container until it drains from the bottom.
Place the container in a warm, brightly lit room next to a window. When grown indoors, the gloriosa lily cannot get enough direct sunlight, so provide it with as much as possible when selecting its location.
Water the soil to maintain a moist soil from spring to fall, never letting it get bone dry nor soggy to the touch. In winter, allow the soil to become much drier to coax the plant into a partial dormancy.
Insert a narrow trellis or multiple plant stakes into the container to provide a scaffold for the climbing stems to clasp and wrap around. Don't pierce the tuber root when you insert the supports.
Apply a well-balanced granular or liquid fertiliser (10-10-10, for example) to the containers in spring and summer according to label directions. Do not fertilise in fall or winter months when warmth and natural sunlight strength is weaker.
Prune the plant by cutting off old flowers with scissors. To rejuvenate the plant or keep it to a more manageable size, cut off all foliage stems in very early spring. The increased day length, warmth and sunlight intensity allows the tuber to quickly grow new stems and foliage. Once new growth appears, increase watering and begin a fertiliser regimen as mentioned in Steps 4 and 5.
In USDA Zone 8, mulch the underground tuber after fall frosts kill back the gloriosa lily's foliage. A 6- to 10-inch layer of bark or straw mulch insulates the ground, preventing it from freezing. This ensures the tuber survives and sprouts new growth the next spring. In USDA Zone 9, winter frosts aren't frequent or severe enough to worry about using a protective mulch. Floridata recommends digging up and replanting the tuber in a new location if the plant loses vigour. Incorporate fresh organic matter in the new planting site's soil.