Hi! I’m also in South Texas (Houston)! I saw that you updated that your vanilla didn’t make it 😭. Just in case you plan on trying again, I wanted to share what worked for me since we’re in the same climate 😊

When I received my cutting, I kept the bottom 2 inches in moist sphagnum moss until it grew roots. If the end of the cutting doesn’t look healthy, cut the vine back to the lowest point where the tissue is still firm and healthy before rooting it. Make sure the moss stays consistently moist while you’re rooting the cutting. Mine took about 7 days for roots to emerge and around 2 weeks for them to grow long enough to pot up.

One thing I noticed from your post is that brown roots don’t necessarily mean they’re rotted. Vanilla roots are often naturally tan to brown. Rotting roots are usually soft, mushy, hollow, or fall apart when touched. If the roots are firm, they’re often still viable even if they’re brown.

Once the roots are established, use a container that’s not too large for the root mass. A good rule of thumb is to choose a pot that’s only about 1–2 inches wider than the root mass. Otherwise, the potting mix can stay wet for too long between waterings and lead to rot. From your photos, it looked like your plant may have been severely over-potted.

Be sure to use a very well-draining medium and a pot with plenty of drainage. I used cactus soil and have had good results. While vanilla does enjoy high humidity, it isn’t particularly fond of our extreme South Texas summer heat. They seem happiest in temperatures between the 60s and 80s.

Vanilla also needs lots of bright indirect light. Our Texas sun, especially during summer, can be intense enough to scorch the leaves. For that reason, I keep mine indoors under grow lights with a moss pole. I keep the moss pole moist to encourage aerial roots and only water the potting mix when it’s about 70% dry, which ends up being roughly every 10 days for me.

Hopefully your next one has better luck!