To prevent morning glories from becoming invasive, regularly trim their vines and manage their growth. Deadheading spent flowers encourages new blooms and limits seed production, reducing their spread. Plant morning glories in contained areas, such as raised beds or containers, to control their expansion. Using supports like trellises helps guide their growth upward rather than sprawling across the garden. Additionally, monitoring for unwanted seedlings and promptly removing them ensures that morning glories remain a beautiful addition without overtaking other plants.