About 20 years ago I was walking beside a small neighborhood creek when I noticed these beautiful yellow flowers partially hidden beneath some tall trees . I Pulled one out, took it home, planted it and it has been multiplying year after year. With some research, I saw similar plants that are referred to as false sunflower or Ox eye sunflower plant (Heliopsis helianthoides) and mine seem to fit this description. There are also different varieties of the false sunflower with double or single flowers.
The Ox Eye sunflower plant is easy to grow but can be invasive. It multiplies each year and I have had to pull them out and discard or give away, However, I would never get rid of them. The false sunflower requires little or no maintenance and can be easily transplanted from one area to the next. All you need to do is pull and out it comes tubers and all. The Ox Eye sunflower is perennial wildflower.
My false sunflower plants have reached up to 7 feet and grow in partial shade or full sun and bloom from mid summer to fall. They flourish in poor soil and drought like conditions. This pattern may vary depending on where it is grown. Butterflies and bees love them and they make great cut flowers.