Here's some cultural notes on the way I raise Gloriosas in large containers:
I usually grow mine in very large containers (14 to 20" +).
I place the tubers (which are often shaped like fingers, legs, or L's) 2 inches below the top of the soil, they are placed horizontally with an inch or two apart, 3 to 6 per container. If using pots or containers, its a good idea to have a trellis in place so as not to accidentally pierce one when soil covered later. They can grow upward (by tendrils at leaf's ends) up to 8 feet per season. It's essential to provide a support for them to grow upward on. The soil must be free draining (adding some sand usually helps). For most of my containers I put a couple inches of styrofoam peanuts in the bottom (this keeps the weight more manageable and helps drainage). Mine usually bloom through the whole summer season. When they decline by fall, taper off watering. I move mine to the basement for overwinter storage. If utilizing large pots, they maybe be left dry in the pots till spring when it is recommended they be re-potted. When tapped out of their old pot an amazing juxtaposition has often occurred in that the tubers migrate from the horizontal plane to become vertical.
I usually fertilize them with liquid Miracle Grow every 2 to 3 weeks.
One can ascertain when they'll come out of their dormancy by observing the tuber tips, they take on a pinkish coloration. At this point it is usually easier to establish which side goes up when planting for a rudimentary eye becomes visible and points upward. The basement here maintains a fairly constant average temperature around 60 degrees.
When grown outside they prefer night temps 60 - 70 degrees but can tolerate down to 50 degrees. Preferred day temps are 75 degrees or higher with high humidity (typical midwest climate).
They can also be grown as houseplants or in the ground summer plants.
At season's end or next season's beginning when extracting them from their habitat it is easy to break them. If that happens be not overly alarmed as usually each separate leg will bloom any way.
To achieve the upward effect I utilize a lot of trellis - a) some are cylindrical that bend inward at the top forming a pyramidal-like closure, about 4' tall, b) some are styled like like the art of Frank Lloyd Wright, single dimensional but 6 foot tall, c) some are box-store single dimensionals of varied heights, I often put 2 or 3 in a large pot and connect them by long strands of wire wrap. The trellis' are usually supplemented by the longest bamboo poles (6'), 1 or 2 per pot. The gloriosas are then secured with a velco-type tie or a green elastic tape like ribbon.
To help stabilize these creations, I use roundular river rock as a mulch with large chunks of rock between stems. This is to offset their propensity to be blown over during summer storms when fully grown.
Some pots sit in large iron plant stands, some on bricks; those (pots) with side drainage holes, on a bed of rocks or concrete.
Pic picked to illustrate trellis' application.
