Luxuriant Sunflower – A RARE Naturally Occurring Hybrid

Gardeners looking a stunning centerpiece to a large flowerbed should consider Luxuriant Sunflower. It’s tall stalks seem to stay erect in most conditions, although this can be virtually guaranteed by doing the Chelsea Chop by the 4th of July. The beautiful yellow flowers swaying in the breeze are attention grabbing as well as mesmerizing. But the bees and butterflies will appreciate the pollen and nectar provided, and you will also attract a lot of finches who love to feed on the seed. So much so that it can be difficult to save any for yourself as the birds are so quick to eat it up!

Luxuriant Sunflower is a tall, stately perennial native to various parts of the United States. A hybrid between Giant Sunflower and Sawtooth Sunflower, it can reach heights of 8′ tall in full sun and moist to medium-moist soil. As far as perennial sunflowers go, this is one of the latest bloomers (although it is rivaled by it’s aggressive cousin, Maximilian Sunflower). But it really does bring in wildlife from pollinators to birds.

Unlike the aforementioned aggressive cousin (looking at you Max!), this species will grow to a large clump roughly 4′ diameter…and no more. So it has rhizomes, but they are just short. Although you may get some self-seeding, which will often revert to one of the parent species. Side note – self seeding from Luxuriant Sunflower…that’s the most likely explanation for how I can to possess several specimens of Sawtooth Sunflowers…but I will save that story and the botanical frustration for another day.

In this article:

Facts

• Luxuriant Sunflower is a hybrid where Helianthus grosseratus is crossed with Helianthus giganteus
• The seed from Luxuriant Sunflower often reverts to one of the parent species
• While some members of the Helianthus genus are quite aggressive, this species is well behaved (from an underground rhizome standpoint)
• In optimum conditions, it can reach heights of 8′ tall. When water or sunlight is less, it will be smaller and less showy.
• One of the latest blooming sunflowers. I have mine blooming in late August into September (PA, zone 6)
• A scattered range, this species has only been documented in a handful of locations from Minnesota to Vermont & Virginia.

Native Range

The USDA lists this plant as native from Minnesota to New Jersey, including VA/MD/DE and several New England states.

I must say though, I disagree with these authorities on the matter. This might seem a bit nit-picky, but my reasoning is that since this is a hybrid of H. grosseserratus and H. giganteus, then it can only be found where both of those species are present. And while H. giganteus has a range that covers parts of New England, H. grosseserratus native range does not go east of Ohio (although it is present in other states). So, any ‘native’ incidence of Luxuriant Sunflower in Virginia to Vermont is the product of a native H. giganteus and a non-native H. grosseserratus.

None of this will have an appreciable effect on anything really, it is just a botanical point. But Luxuriant Sunflower should not exist (naturally) unless both parent species are present, which is illustrated in the map below:

Reference Table

Scientific Name	Helianthus × luxurians
Common Name(s)	Luxuriant Sunflower, Helianthus Luxurians
Native Range, USDA Zone	North Central to East United States, USDA Hardiness Zones 4-8
Bloom Time	Late summer
Bloom Duration, Color	Six weeks, Yellow
Height	4-8′
Spacing / Spread	4′
Light Requirements	Full sun to part sun
Soil Types	Sandy loam to clay
Moisture	Moist to medium-moist
Fauna Associations / Larval Hosts	Bees, butterflies, birds / Silvery Checkerspot and Gorgone Checkerspot

What are the Benefits of

Beauty

Sunflower blooms are always beautiful, and this species is no exception. The canary yellow to gold blooms are exquisite and gorgeous, especially on windy days when they blow in the wind.

Wildlife

Members of the Helianthus genus are extremely valuable to wildlife by directly providing food for pollinators, hosting pollinators, feeding birds, and small mammals/rodents. All of these creatures are part of our larger ecosystem, and they in-turn feed other animals from hawks, owls, foxes, etc.

Tough

This is a strong and highly disease resistant plant. Once established, it is tough to kill or remove! But that means it is resilient to deer browsing, and just about anything else!

Contained

This plant does not spread like some other perennial sunflowers (see here and here). It has short rhizomes, which will form a clump that is roughly 4′ diameter.

Identification and Characteristics

Stalk

The stalks will reach heights of 8′ depending on moisture and available sunlight. There is generally no branching until the top where the inflorescence occurs. The stalk is generally erect, green to red in color, and will be covered with small hairs.

Leaf

Leaves are alternate to opposite, 4-8″ long by 1″ wide, covered with tiny white hairs, and will grow on short 1/2″ stems. The shape is linear to narrow lanceolate, and the margins are slightly toothed. You really have to look close to see the margin teeth, as they are not well defined/deep.

Flower

The daisy-like flowers are 2-4″ diameter, canary-yellow, and typically have 10-20 petals. In the center of the flower are dozens and dozens of disc florets that are a more golden color.

Root

The root system is fibrous roots and short rhizomes. After several years my primary plant grew to an approximate 4′ clump. But it hasn’t ever spread beyond that in 7 years.

Growing Conditions

For growing conditions, Luxuriant Sunflower does best in full sun but can tolerate part-sun. It is moisture loving, and will do best in a full-sun / moist environment. But I can tell you that my own plants have experienced severe drought with no supplemental water and they survived. However, the plant doesn’t produce as much blooms, and the stalks don’t grow as tall during drought.

Propagating Luxuriant Sunflower

Since this plant is a hybrid, it is incredibly rare to find seed. You almost would have to make it yourself, by hand pollinating a bloom of Sawtooth Sunflower with pollen from Giant Sunflower. That being said, you can easily dig out a rhizome in Spring when the plant is emerging. Just use a spade and chop them away from the end of the plant. Pot this up or transplant it to a new location with full sun and moist to medium soil and it will grow just fine. I actually have two containers with this flower that have survived for two full years (I always forget to plant them).

It is a good idea to shade the divided plants, whether in containers or the ground, for several days until the ‘transplant shock’ wears off.

Wildlife, Pests, and Diseases

Pollinators

This plant will attract a wide variety of bees (they are the primary pollinators). But you can also see various butterflies visiting for nectar, even late season migrating Monarchs. The parent species do host numerous caterpillars, and it is likely that this one will too^[3][4].

Deer and Rabbits

Rabbits generally don’t bother this plant, as it jumps up quickly and gets out of their reach. Deer however will browse the foliage when it is tender and new. Once a leaf is fully formed though, they tend to leave it alone. This may be due to the small hairs that cover the leaf.

Disease

Luxuriant sunflower is generally disease free. It is unlikely you would have any problems.

Where you can buy Luxuriant Sunflower

Unfortunately Luxuriant Sunflower is not typically sold in nurseries. In fact most perennial sunflowers are not. This one is pretty rare as it is a huge flower, and a hybrid. It may be available native plant nurseries though, but you should call and check. You can find native plant nurseries near you on our interactive map.

Where to buy seeds

Unfortunately, as of now there are zero places to purchase seed of this plant. The fact that it is a hybrid means that nobody could produce it without cross pollination, which would be fairly unreliable. I got this plant through a mistake of a seed company. I tried to purchase Helianthus giganteus by this grew instead, and I was blissfully ignorant until a YouTube commentor pointed out that the flower was Luxuriant Sunflower.

Thus, if you really want seed from this flower you are probably going to have to get them yourself by creating a hybrid between H. grossessaratus and H. giganteus.

Uses of Luxuriant Sunflower

Garden Uses

The overall size of Luxuriant sunflower means that it is a bit limited where you can put it. That being said, you can make it the focal point of a flower bed provided or use it as background of a meadow or prairie garden. You could even use it as a component of a living fence!

Companion Plants

This plant pairs well with other tall plants that like similar conditions. Some examples would be the parent species, Sawtooth Sunflower, Tall Sunflower, Tall Coreopsis, and the Compass Plant. Other tall grasses would do well such as Big Bluestem or switchgrass.

Final Thoughts

My growing of this plant turned out to be a happy accident, and what is cool about it is that I ended up with a rare, but lovely flower. The benefits it brings from aesthetics and wildlife make it a great component of my garden. Thus, I’m happy to have it, and I think it’s cool that I have such a rare plant.

Find more native plants here