This is helianthus giganteus, commonly known as giant sunflower. I bought four plants at a community plant sale last May and stuck them at the back of the border, so they would be against the deck railing. These are perennials, unlike the big-headed annuals.
Well, they kind of took over the entire bed. They’re supposed to grow to about 10 feet tall, but mine seem to be 12 feet or taller. They were late to flower, but now they look great, and the pollinators are loving them, too. Here’s a clump next to my lonicera “Major Wheeler,” another favorite plant.
Maybe this will give you a better idea of how big these plants are.
The one fault I have found is that despite their thick stems, they are not that sturdy and will blow over in strong winds. I have done by best to resolve that by tying them up to the deck railing, but I have still lost a few plants.
Here’s a shot of one of the flowers, which are respectable but not overwhelming. The leaves are huge, though.
Here’s what the plants look like when I’m standing on the deck.
I am all about color in the garden, and this is a most colorful display at a time of year when a lot of plants are winding down. If I remember, I paid $4 for all the plants, which, if you consider their impact, is most respectable bang for my buck.