I have an Hoya Carnosa that I have had for about 10 years. Living in Tucson, Arizona I keep it on the back porch, south side of home. No problems until this year when the temp dropped to 19 on the porch. My hoya froze somewhat. Lot of leaves have turned yellow. Should I clip it all back, hate to lose the flower nodules as it blooms profusely every year. This was started from a cutting which I rooted in just plain water. Got lucky from everything I read.