The problem might be too much hot wind.I'll recommend you soak this plant in the morning and in the evening-try to water the base of the plant and not get the flower buds wet.Avoid too much fertilizer...MG's bloom better with lower nitrogen.

Although the premise of nutrient deficiency, has plausibility, I believe your condition is normal, especially Heavenly Blue. This, of course is assumming you also have good growth as well. Are you just showing the bottom leaves, which, incidentally, look exacly like mine? The tops are growing rampantly, and even though a large proportion of the plant died back it was quickly covered by new growth. Several people here have mentioned the chlorosis of the lower to mid leaves, as the plants way of maintaining growth where it is needed, as it climbs hight into the sunlight. That being said, If your entire plant is suffering, I would say you have a magnesium deficiency, especially in sandy soil, and non humus rich soils. Epsom salts at the rate of 1 tbls a gallon might help, although the plant foods mentioned also supply this micronutrient. Note~*, the degree to which I have had interveinal chlorosis, followed by yellowing and then browning and leaf drop, has lead me to use a suppliment of Epsom salt, especially after alot of rain, which tends to wash out magnesium in sandy soils. Can't say it is a cure, but I can say that my Heavenly Blues are going nuts. Even though they continue to loose leaves, (bottom looks horrible) the rate of new growth is astonishing and they are beginning to flower profusely.

Hello Susan - The Ipomoea tricolor does like full sun but it will acclimate to what it usually exposed to...and leaves can get sunburnt (just like humans) from the ultraviolet rays if they are not exposed to direct sun gradually. The peripheral areas of the soil in your container look to be dry and I see no water reservoir under the container... Ipomoea tricolor is not native to areas that cannot supply enough water to keep it alive , otherwise it could not survive in areas which are too arid. Ipomoea tricolor can surely be grown successfully in arid areas if it is supplied with enough water to offset whatever water is evaporated directly and / or indirectly. The placing of the containerized plant directly in the sun allows the sun to heat the leaves , the surface of the growing medium, the container sides (and thereby add to heating the entire growing medium) and anything in the general area under and around the growing container. The plant leaves respire and water will evaporate out of the pores as well as from the growing medium. I suggest that you do something to insure that the plant has enough water available so that it can replace whatever water gets evaporated and it will then be able to withstand full sun. Please remember that growing plants in containers is NOT the same as when the roots are planted directly in the ground , because the sun will heat the entire container and the roots get heated in a way which would not occur when the roots are directly in the ground and this causes the plants to be much more susceptible to an unhealthy type of dehydration . You can also try placing some type of top layer like a coarse mulch (e.g., bark) which will help to conserve moisture and wrap the outside of the container in a reflective material like colored aluminum foil to reflect heat off of the sides of the container. Reflective material can be used effectively over the top of any water reservoir to help insure that the water doesn't get evaporated directly from the sun and is therefore more available to the plants roots... The placement of a reflective material (e.g., mirrored surface like mylar) can also be placed underneath the water reservoir and extending outwards to some degree to reflect all light upwards towards the plant leaves . The reflective materials strategically placed help to prevent the area underneath the container from heating up too much to where it may be contributing substantially to additional and / or excessive heat from underneath the growing container. I hope my suggestions may be found to be useful... regards, Ron This post was edited by ron_convolvulaceae on Wed, Apr 24, 13 at 14:30

Hi xenofenix - Could you post(or send me) photos of what different types that you have so I could provide some relevant feedback... Thanks(!) Ron Here is a link that might be useful: Ipomoea species with photos in the PlantFiles