Answer: Thunbergia alata seeds are widely available in the spring if you would like to start the plants yourself.
Or, you should be able to save seeds from your plants to plant in the spring. Once a flower fades and the petals drop off, there should be a swollen embryo left on the vine where the petals used to be attached. This is where you will eventually find the seeds. Wait for them to mature. When they ripen, they will rattle inside the pod and it will be drying out and begin to crack open. Air dry the seeds on a piece of paper for a week or two, then save them in a paper envelope kept in a cool dry location. The seeds need a warm soil temperature to germinate but grow quickly.
You might be able to root tip cuttings and grow them on in hanging baskets, however these plants need so much intense sun to stay healthy that keeping them going vigorously over the winter is difficult without a greenhouse. I hope this gives you some ideas.
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