98-105 days. Madness Series petunia seeds are an easy way to splash some early-blooming and exotic accent to your home or garden all season long. Madness petunia seeds promise stunning 3 inch wide blooms bursting with over 20 eye-catching colors to choose from. Madness Series petunias mature into neat 10-15 inch tall mounded uprights perfect as a tidy grow for borders, edging, ground cover, or hanging baskets. Madness petunias are easy to grow from seed and are an ideal way to rejuvenate any tired flower bed, porch, or office. Pelleted seeds.