Perennial Sunflowers

Helianthus maximiliani - Maximilian sunflower_DBG_20090915_LAH_0606

It’s January, but my brain is in July. I need to imagine warm breezes, green leaves, and most of all, bright flowers. And what is more reminiscent of a hot, summer day than a bright yellow sunflower? When we think of sunflowers, the image that comes to mind is a large brown disk surrounded by brilliant, sunny petals, kind of like this:

Sunflower_ColoSpgs-CO_LAH_4950

These sunflowers are annuals, Helianthus annuus. They can be planted by a gardener, or by the birds, but someone has to stick that sunflower seed in the ground every spring if you want to enjoy the huge blossoms come summer.

Helianthus pumilus_Dwarf Sunflower_DBG_LAH_1625But did you know there are perennial sunflowers as well? In fact, there are a number of named cultivars, all in the genus Helianthus, such as H. salicifolius (Willow-leaved Sunflower), H. ‘Happy Days’, or the Rocky Mountain native H. pumilus, the Little Sunflower (right). But there is one stand-out when it comes to perennial sunflowers: Maximillian Sunflowers (Helianthus maximiliani).

Imagine plants 3 to 10 feet tall and 2 to 4 feet wide, with many lateral branches, and each branch with dozens of showy yellow blossoms from mid-summer until frost. These flowers resemble their annual cousins in having an aura of yellow petals around a central disk, but they’re about 4 inches in diameter—smaller, but still plenty big enough to make an impression. Besides, their smaller size is more than compensated for by their sheer numbers.

And just think—all this and you don’t need to sow new seed every year. Maximillian sunflowers are hardy in USDA zones 4 through 9.

Being native to the central U.S., Maximillian sunflowers do very well in Colorado. Just give them an occasional drink during dry spells. The plants are remarkably tough, tolerant to drought, poor soils, and even browsing deer. Sow seeds or set out transplants in full sun, and avoid over-fertilizing or over-watering—being too nice just results in floppy, overgrown plants. Taller specimens may require staking, especially in windy areas.

As you’d expect from their size, these sunflowers are best placed to the rear of a border where they’ll have plenty of room, or in a naturalized meadow or prairie garden. Insect pests and diseases are unlikely, but the flowers attract butterflies, and the seed crop is relished by birds and other wildlife.

Maximillian sunflowers aren’t for the faint-hearted. You can’t help but notice their presence in the garden. But if you’re looking for a stand-out plant that’s ideally suited for an eastern Colorado garden, give this perennial sunflower a try. You’ll be impressed!

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