From my perspective as an Ipomoea lobata plant, the most fundamental reason I may not be flowering is simply that I am not yet ready. Flowering is an energetically expensive process, reserved for when I am mature and strong enough to support reproduction. If you started me from seed late in the season, or if the conditions have been less than ideal for my growth, I am likely still focusing all my energy on establishing a robust root system and producing vigorous vines. My priority is survival first. Once I have sufficient leaf mass to photosynthesize effectively and a root system that can gather enough water and nutrients, I will naturally shift my energy towards producing my distinctive, multicolored flower racemes. Please be patient with me; I am working hard to get there.
Sunlight is my food. It is the fuel that powers everything I do, and flowering requires a tremendous amount of energy. If you have planted me in a spot that receives only partial sun or is shaded for a significant part of the day, I am literally running on empty. To produce flowers, I need a minimum of six hours of direct, unfiltered sunlight each day. More is even better. When light is insufficient, my stems may become long and spindly as I stretch desperately towards the light (a process you call etiolation), and my leaves may be fewer and smaller. In this state of energy conservation, flowering is a luxury I cannot afford. For me to bloom, you must place me where I can bask in full, glorious sunshine.
Your intentions are good when you fertilize me, but the type of fertilizer you use is critical. If you are giving me a fertilizer with a high first number (Nitrogen), you are encouraging me to focus entirely on vegetative growth—making more and more leaves and vines. While I appreciate the lush, green foliage this produces, it directs my energy away from flowering. What I need to initiate blooms is a fertilizer higher in phosphorus (the second number on the package), often labeled as a "bloom booster." Phosphorus is essential for flower and root development. An overabundance of nitrogen keeps me in a perpetual state of leafy adolescence. A balanced or phosphorus-rich feed will signal to my internal systems that it is time to shift priorities from growth to reproduction.
My root system is my foundation, and its health directly impacts my entire being, including my ability to flower. There are two common root-related issues. First, if my roots are sitting in waterlogged, poorly drained soil, they begin to suffocate and rot. A stressed, oxygen-starved root system cannot effectively transport water and nutrients to my vines, leading to overall weakness and a complete lack of flowers. Conversely, if you allow the soil to become too dry for extended periods, I become drought-stressed. While I am somewhat tolerant of dry conditions, severe water stress will cause me to abort any flower buds as a survival mechanism. Consistent moisture, without being soggy, is the key to keeping my roots happy and productive.
I understand you may want to control my shape, but timing is everything. If you prune my vines too late in the summer, you might be inadvertently cutting off the very stems that were preparing to flower. My flowers develop on new growth, but that new growth needs time to mature and initiate buds. A late-season pruning can remove these potential flowering sites, delaying or eliminating my display for the year. If you feel you must prune me, it is best to do so earlier in the season to encourage bushier growth, which can actually lead to more flowering points, or to simply deadhead spent flower racemes to encourage new ones to form.
