Hoping this reply doesn't come too late. From your description, it sounds like your morning glory has sun scald - basically a plant sunburn. If you live in the hotter part of India, direct sun might be too much for the morning glory. I used to live in a warmer part of the US - Oklahoma, USDA zone 7 if that helps - and I had to plant my flowerbeds on the side of the house that got the most shade. My morning glories did really well with only about 4-6 hours of direct sunlight.
Another trick I learned there, was to water in the evening or at night, never in the morning or during the day. High temperatures can cause the fresh water to steam the plants, which can cause yellowing and wilting, but I don't think it would cause the crispy edges like you'd find with sun scald. But, watering in the evening gives the plant more time to absorb more water, before it evaporates, so it also helps conserve water :)
Hope this helps! Happy gardening!!
Hoping this reply doesn't come too late. From your description, it sounds like your morning glory has sun scald - basically a plant sunburn. If you live in the hotter part of India, direct sun might be too much for the morning glory. I used to live in a warmer part of the US - Oklahoma, USDA zone 7 if that helps - and I had to plant my flowerbeds on the side of the house that got the most shade. My morning glories did really well with only about 4-6 hours of direct sunlight.
Another trick I learned there, was to water in the evening or at night, never in the morning or during the day. High temperatures can cause the fresh water to steam the plants, which can cause yellowing and wilting, but I don't think it would cause the crispy edges like you'd find with sun scald. But, watering in the evening gives the plant more time to absorb more water, before it evaporates, so it also helps conserve water :)
Hope this helps! Happy gardening!!