Q.Impatiens
New leaves on my impatiens are smaller than old ones. Why is that? How can new growth of leaves be larger?
When your plants began to get leggy, you can cut them back to improve their shape and condition.
Cut them back to about half of their size at planting time.
Make the cuts about 1/4 inch above a set of leaves.
This will rejuvenate your plants for the later part of the growing season.
https://www.gardeningknowhow.com/ornamental/flowers/impatiens/growing-impatiens-flowers.htm
https://www.gardeningknowhow.com/ornamental/flowers/impatiens/impatiens-problems.htm