I am sorry for this delayed reply to your gardening question. We are transitioning to a new Q&A system and your question was unfortunately lost in the transition. I have discovered it now and hope this reply is not too late to be of help.
I am not aware of such problems on a trumpet vine. Madame Galen has proven very good at blooming in Texas having seen such vines as far south as the Conroe area north of Houston and the San Marcos area north of San Antonio.
Sometimes vines growing in very rich soil conditions tend to be overly vigorous at the expense of blooming. Avoid fertilizing and don't provide more water than is necessary to keep the vine going. Make sure the vine is getting full sun as in shade they lack the energy to produce the carbohydrates needed for bloom production. Finally, if all else fails you might try root pruning as this is often used on wisteria to slow the plant down and back up some carbohydrates to induce bloom. To root prune, push a shovel into the ground about a foot out from the vine in 2 or 3 directions. You might start with one spot and then watch the vine for a day or two to determine if it is drooping too much before making the second or third pruning with the shovel.
Thanks for the question. Please stop in again soon!
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