Your morning glory is growing exactly as it should. There is nothing you can do to change it's shape or size because this is how this particular JMG grows.

Looks really nice in your pic, healthy and happy

See link below for more info

Fran

Here is a link that might be useful: info and pics of JMG Kikyouzaki Murasaki

Welcome to the wonderful world of growing morning glories. You have a double flower, congratulations. It is normal size, petite and cantik.

Thanks for your info Fran and Gerris2.

Do you grow your plants where you give them protection from the intense tropical sun?