You have a beautiful sunflower in your yard, except you didn’t plant it there (probably a gift from a passing bird) but it looks nice and you want to keep it. You may be asking yourself, “Is my sunflower an annual or a perennial?” Read on to learn more.
Annual and Perennial Sunflowers
Sunflowers are either an annual (where they need to be replanted every year) or a perennial (where they will come back every year from the same plant) and telling the difference is not that hard if you know how.
Some differences between annual sunflowers (Helianthus annuus) and perennial sunflowers (Helianthus multiflorus) include:
- Seed heads – Annual sunflowers can have either large or small seed heads, but perennial sunflowers have only small seed heads.
- Blooms - Annual sunflowers will bloom the first year after being planted from seeds, but perennial sunflowers grown from seed will not bloom for at least two years.
- Roots – Perennial sunflowers will have tubers and rhizomes attached to their roots, but annual sunflowers just have the typical string like roots. Also, annual sunflowers will have shallow roots while perennial sunflowers have deeper roots.
- Post winter emergence – Perennial sunflowers will start up from the ground in early spring. Annual sunflowers growing from reseeding will not start to show up until late spring.
- Germination – Annual sunflowers will germinate and grow rapidly while perennial sunflowers grow much more slowly.
- Seeds - Non hybridized perennial sunflowers will have relatively few seeds since it prefers to spread through its roots. The seeds also tend to be smaller. Annual sunflowers spread through their seeds and, because of this, have many large seeds. But because of modern hybridization, there are now perennial sunflowers that have more seeds on their flower heads.
- Growth pattern – Annual sunflowers tend to grow from a single stems spaced out from each other. Perennial sunflowers grow in clumps with many stems coming out of the ground a tight clump.