Question: My African violets always seem to develop long "necks"—their main stem has a long section that's bare of leaves. What can I do to correct a long neck on an African violet?
Answer: I was about to suggest a lack of sufficient light as the cause of this problem, but in reading a few articles at the African Violet Society of America website—www.avsa.org—I learned that a "long neck" is actually a normal behavior for an African violet!
These plants grow new leaves from the center—which is also the top, though we don't generally think of them as having a top and bottom, since typically they look rather flatly circular. As the new leaves develop at the plant's top, old leaves as the bottom die off (usually they start looking ratty and we remove them). Since new leaves grow only from the top, the plant will eventually end up with a stretch of bare stem.
Joyce Stork, co-author of You Can Grow African Violets, recommends aggressive treatment to correct this problem:
1. Remove all the flowers and all the lowest, oldest, largest leaves, keeping just those that look healthy and are roughly the same size. The plant will survive even if only three or four leaves remain.
2. Gently scrape the two inches of stem below the lowest remaining leaves, using a dullish blade, such as a butter knife. Scrape off the surface layer of tissue and even off the places where leaves once grew.
3. Cut off the top of the plant, cutting at the bottom end of the section you just scraped. You're going to pot this part, and roots will form from the scraped stem.
4. Check to make sure the interior of the stem looks healthy. If it has any brown patches, it is rotting. You can try cutting farther up on the stem to see if that part is rot free, or you can give up now.
5. If the stem looks clear of rot, fill a pot with fresh growing mix (houseplant soil with added vermiculite or perlite works well for violets) and dampen it thoroughly. The pot should be the same size as the one that held the plant before this operation.
6. Insert the bottom of the stem into the potting mix. If the stem is bent, push it straight down into the soil. (This will make the top growth sit askew, but it will straighten out over time.) Seal the pot in a clear plastic bag or put it into a closed terrarium and place it in bright but indirect light. Leave it alone and in about a month you should see new leaves beginning to form at the top/center, meaning the stem has rooted. Open the bag or terrarium and let it sit there for another day or two to acclimate to the fresh air. Then you can remove it entirely and care for your plant as you were previously.
One last point. If the neck is curving, you do probably also have a light issue. The plant was likely growing toward the window. One way to keep an African violet growing straight is to give its pot a quarter turn every week.