Mt. Cuba trials gave Citronelle a 4.7 out of 5.0, implying a very high quality, vigorous cultivar:
But I tried to grow it several years ago and lost it.
This year I planted numerous Heucheras, some in the ground and some in pots, and all did well. I watered them until they were established, but the rain here was sufficient and well spaced for most of the summer, so it was not necessary to water most of the time. Cultivars are shown in my plant list.
I have been very pleased with the vigor of all the Heuchera cultivars I planted this spring. Caution: none were light green like Citronelle, so I may have selected particularly vigorous cultivars.
I have one cultivar, Peach Melba, planted several years ago (same year I planted Citronelle), that has struggled in a near-death state ever since I planted it, so I know from first-hand experience that there are dramatic differences in vigor among Heuchera cultivars.