After awhile the plant will start to decline. To keep it going and looking fresh each year, you will have to do cuttings.

Camelliag,
How is your plant doing? I also love the doubles, just like mini roses but easier to take care of! I "inherited" a pink double last fall. My paternal grandmother who passed away in 1984 had given my mother a cutting. My mother kept the plant going all these years (not the original plant, of course) but she is now 82 and decided last fall when it was time to bring the plant in that it was time for me to become the caretaker. She is tired of the responsibility but could not bear to let it die for sentimental reasons. I brought home a pot and let it overwinter in the guest bathtub under a grow light where it bloomed all winter. I also took a couple of cuttings just in case the potted one didn't make it. When it started getting leggy, I just pinched back the stems and it sprouted out healthy new growth. It has now transitioned back out to the porch for another season.
From reading your post I noticed you said you watered yours when they "look thirsty". By the time they look thirsty they are already stressed, you might try more frequent watering. Also, you said they are in shade all day. Is it deep shade? Where I live I have had good luck with early morning sun as long as there is plenty of moisture.
Mechele

My double impatient's leaves have started rowing over and it has small white stops on them. What should I do to take care of my plant?