The short answer: anywhere from ankle-height to taller than a house — it all comes down to the variety. Here's what to expect from each type, how tall they get in the UK, the world record, and how to push yours higher.
"Sunflower" covers a huge range, so there's no single average — but here's the realistic picture for each group:
So the "average" sunflower most people picture — a single tall stem with one big golden face — usually lands around 2 metres. If you want more, you need a giant variety and the right care.
In a good British summer, a standard sunflower comfortably reaches 1.8–2.5 m. Giants can pass 3 m, but the UK's shorter, cooler growing season means they don't usually match the towering heights seen in warmer countries. The trick here is to start early — sowing giant varieties indoors from mid-April gives them the long season they need. See our sowing calendar and how to start seeds for the timing.
The tallest sunflower ever recorded reached over 9 metres — roughly 30 feet — grown in Germany. That takes specialist giant genetics, a very long season and years of expertise. But don't let that put you off: a well-grown giant in an ordinary garden can still reach an impressive 3–4 m. See the full list of record heights on our sunflower records page.
Height comes down to five things: the right variety, plenty of sun, deep and rich soil, steady deep watering, and a long season. Choose a giant, feed it well, water deeply to encourage deep roots, and shelter it from wind. Our growing tips cover the full method for chasing maximum height.