Just wanted to tell the author of the article about Red Valerian that it is CENTRANTHUS Ruber NOT Ceranthus......
We have 2 new Jupiters Beard plants and they have curling yellow leaves. Any recommendations please? Thank you!
This appears to be a fertilization, or pH related issue. First you should try putting dolomitic lime on the area to control the pH. If this doesn't fix the problem then the next thing to look at is a nutrient deficiency. This is most likely a lack of nitrogen if it isn't the pH causing it. Here is some more information: https://www.gardeningknowhow.com/edible/herbs/valerian/growing-jupiters-beard-plant.htm