“黑疙瘩头”是牡丹较为常见的病害,属真菌性病害,称紫纹羽病。由于靠土壤传播,为根部发病,初期呈黄褐色,后为黑色,花农称之为“黑疙瘩头”。得病原因,据多年人工深翻地观察,是由高温高湿引发。凡是根系下层有不透水(胶泥层)的牡丹,“黑疙瘩头”的特别多。患此病3年以上的病株可全株死亡。易感染此病的有不耐湿的品种:‘朱砂垒’、‘胡红’、‘金鱼交章’、‘赵粉’等。这里介绍一种染病3年以内的病株复壮法: “Black knot head” is a peony more common disease, is a fungal disease, said purple line feather disease. As spread by the soil, the root of the disease, the initial was brown, after the black, flower growers called “black pimple head.” The cause of the disease, according to years of artificial deep flip observation, is caused by high temperature and humidity. There are impervious water (clay layer) peony under the root of the bottom, “black pimple head” is particularly large. The diseased plants suffering from this disease for more than 3 years may die completely. Easily infected with the disease are not wet varieties: ’Cinnabar barrier’, ’Hu Hong’, ’goldfish chapter’, ’Zhao powder’ and so on. Here to introduce a disease within 3 years of rejuvenation law: