As you wrote, Serissa is a little fussy. This means 3 things for you: 1) Find out what specific things make it happy in your climate (Sun, water, fertilizer, temperature, etc, 2) Do those exact things, and 3) Don’t change anything, or change as little as possible. For example, if it gets too cold outside one night, consider putting it in your unheated garage instead of in your heated house at night to minimize the temperature fluctuations.
As others have mentioned, you also might consider buying a few more trees so that you can practice more and learn more. I’d suggest that you get some from your local Home Depot or nursery because they will be cheaper, and you may find it very rewarding to turn a “regular” tree into a bonsai over time. You’ll probably want to look for trees that are hardy (more forgiving when you make mistakes) and fast-growing (so you can see results faster). Other people can recommend more trees that would do well in Alabama, but some good possibilities may include Chinese Elm, pomegranate, olive, bougainvillea, and any kind of juniper. Boxwoods are great, cheap, easy to find, and are hardy, though they tend to grow a little more slowly.
Miracle Grow is a great fertilizer for you, just don’t fertilize during the winter,
Welcome to the site, and I hope you find as much pleasure in bonsai as we do.
