All plants will grow in soft water. Plants tend to only melt when there is a significant change in the KH of the water they came from to the KH of the water they currently inhabit. The KH break points appear to be approxiamately 4-6 and 10-13 in my experience. Usually, if the nutrients are right and they have the proper amount of light, they will melt and regrow (sometimes from almost nothing at all). If they have an adequately established root system, they normally will regrow.