Perennial Sunflower

Flowers of perennial sunflower, 'Flore Pleno'
'Flore Pleno' perennial sunflowers

‘Flore Pleno’ Perennial Sunflower (Helianthus multiflorus ‘Flore Pleno’)

A surprising find, ‘Flore Pleno’ is a full, yellow, perennial sunflower that lasts super long in the vase—at least two weeks. I don’t know why it’s not in nurseries, but it’s okay with me if we keep it as our little secret. It’s so nice to have a few flowers that are nice and easy to grow, yet no one else knows about them!

Pollinators like it, too.

Flowers

The flowers resemble chrysanthemums and are up to 4” wide with long sturdy stems. They bloom by the fourth of July where I am in the northern Sierras of California. I once had a bouquet made with them that ran out of water, and I saw no wilting at all.

Keep them deadheaded for continuous flowering. But at the end of the season, letting the last flowers go to seed will attract birds, especially goldfinches.

'Flore Pleno' perennial sunflower in a bouquet
'Flore Pleno' perennial sunflower in a bouquet

Plants

This perennial sunflower gets 4-6ft. tall. It makes a nice summer hedge with big yellow flowers. It’s an herbaceous perennial.

It’s good in a perennial flower bed, but not deer resistant.

Growing the plants

These require full sun, or you’ll get powdery mildew. Remember that full sun means 6 or more hours of direct sun.

I give mine average water, not real dry conditions but I let them dry out well between watering sessions. For my location and soil I water once every one to two weeks, depending on temperature.

Start these as plants, they’re not available as seeds because they’ll be a genetic toss-up and you won’t know what the flowers would be like (see plant genetics). But they do form a clump that can be divided every few years.

If you’re a good propagator you’ll be able to start plants each year from small rhizomatous shoots. Or wait until there’s a larger clump and divide bigger sections.

Full-petaled yellow flower on plant with wide green leaves
'Flore Pleno' perennial sunflower in the garden

Harvesting

Cut and treat these the usual way. The stems are long and should be cut down to a node for good side flowers.

Favorite varieties

There are other perennial sunflowers but this variety is unique on its own and excellent quality.

How many plants

How many depends on what you want them for and how much space you have. If you start with just one, you can keep propagating them by dividing or breaking off the root shoots. But it will take a few years.

Sources

The way I found this plant was by looking through the Bluestone Perennials website. It’s the best source. I’ve also found that Goodness Grows carries it.