Ask Mr. Smarty Plants

Let's begin by seeing what we know about Merremia dissecta (Noyau vine); "Alamo vine" is another common name. This USDA Plant Profile Map shows that it grows in Travis County, and since you are right on the border of Williamson and Travis Counties, there should be no problem there. According to our webpage on this plant, which you can read by following the plant link above, it blooms white from May to November, and needs to be in sun (6 hours or more of sunlight a day) or part shade (2 to 6 hours of sun a day). Its water requirements are low to medium, and it likes a moist or dry soil. It is a member of the Convolvaceae or morning glory family, and can be quite aggressive.

At this point, the only thing we can identify as a possibility for non-blooming is to ask when you planted it? It is a perennial, and most perennials don't begin to bloom until their second year in the ground. As to fertilizer, no. In the first place, most native plants don't need fertilizer, and some actively dislike it. In the second place, fertilizing a plant that you wish to bloom will only discourage the blooms, especially if it is a high-nitrogen fertilizer. That encourages leaves to grow, and is often used for lawn, because that's what you want from a lawn-green leaves. If a fertilizer has been applied to nearby lawn or in the bed the Alamo vine shares, that could be inhibiting, rather than encouraging the bloom.  Finally, as hot and dry as it has been, and especially if it has been fertilized with nitrogen, the plant may be using all its energy to stay alive and keep leaves going to manufacture the nutrients for the tree. All plants must bloom in order to set seed in order to propagate themselves, so it should bloom, but it might be later rather than sooner. Make sure it's getting enough water and light. Beyond that, we prescribe patience.