How to Grow Broomcorn in the Garden (and for Floral Design)

Broomcorn (Sorghum vulgare) is one of our favorite floral materials to grow in the garden and in arrangements, especially in the fall and is also one of our annual favorite grasses to grow!

Broomcorn is not actually corn - it’s not a member of the Maize family - but is instead an ornamental sorghum - distantly related to sugarcane and big bluestem grass interestingly enough.

It usually grows as a single corn-like stalk, soaring upwards above our heads and growing quickly into a towering stalk of strappy foliage and bamboo-like stems, creating a jungle-like effect in the garden.

Drought tolerant and seemingly thriving on neglect, broomcorn pops up all over the garden and is always a welcome sight for both the garden as well as for floral design. It’s such an easy and versatile plant to grow that even a beginner gardener could grow it with no issue.

Growing Broomcorn

Broomcorn can be transplanted, but it’s so easily direct sown that it’s not not really worth it to me to start broomcorn - especially when there are so many other plants that I’m starting at the time.

If I’m planting for harvesting smaller tassels, I’ll plant them closely - every four inches so that they support each other. If I’m planting for larger tassels, I’ll plant every six inches to give them a bit more space and let them get nice and big.

It’s important to realize that broomcorn have weak stems that naturally will bend and collapse if it gets too tall (farmers actually will prematurely bend over broomcorn to allow the tassels to lengthen into broom-length) so you can either work with their naturally bend-y nature and harvest the tassels that way or you can prematurely pinch them.

To pinch broomcorn, pinch out the growing tip when the broomcorn get to around three feet tall. This will halt the growth of the central stem and force it to put growth into side shoots, which will be smaller but more numerous. Make sure that you pinch out the broomcorn earlier on in the season so that it has enough time to put out multiple side shoots and bloom.

Broomcorn are very drought tolerant but do well with heat and humidity as well. They do best with lots of sun, but will also do well in part shade, growing more skinny and leggy as opposed to the ones in full sun that are more squat and leafy.

Broomcorn don’t need constant moisture or a lot of fertilizer, but will get bigger and grow better with regular watering and good soil. Our best broomcorn grows in well amended soil, reaching heights of twelve feet with giant plumes - but they’ll do fine in poor soil as well, just not getting quite as big.

Composting Broomcorn

There is one issue with broomcorn - and that is that the plants themselves with the stalks are incredibly tough.

If you’ve ever tried to yank a broomcorn out of the ground, you’ll find that their stems are very firmly rooted to the ground. This little (but tough) root system is even more difficult to remove after harvesting, becoming almost stump-like in their nature.

You can prevent having to have a hassle with the roots of broomcorn in one of two ways:

1) Let the broomcorn freeze and compost in place

or

2) Pull the entire plant out at the time of harvest.

I honestly prefer the second approach - we don’t freeze and thaw enough to really decompose broomcorn roots! - and it makes sure that the beds are clean and prepped for replanting as you harvest the broomcorn.

The stalks themselves are also very sturdy - becoming almost bamboo-like in structure and toughness - and if you don’t have a way to get rid of them, you’ll be left with a lot of tough, woody-like stalks that won’t break down quickly.

If you’re interested in composting them, it’s important to chop them up into small compostable bits. If you want to get rid of them without composting, you may be able to find a market for them in fall by tying them into bundles and encouraging people to decorate their front porches and foyeurs with these broomcorn-stalk sheaves.

Our Favorite Broomcorn Varieties

Texas Black is by far our favorite, flowering with big glossy midnight-black seeds that are like little obsidian beads on the wiry broomcorn stems, and the one that we’ve grown for years. The black seeds are a wonderful punch of darkness and saturated color among the tan and browns of most dried materials.

Red is another favorite, and is especially floriferous with up to 5 stems per plant. The bright golden-red of the seeds is absolutely beautiful with the sunny bold colors of fall, and are an especially nice accompaniment to mums and pumpkins or enjoyed in the garden on their own when backlit by the evening sun to reveal a fiery glow of color.

If you don’t want to commit to a certain color, the Colored Uprights come in all shades of the broomcorn rainbow - red, gold, black and burgundy. Especially if you’re bunching these together for dried floral bouquets, the variety in color will help to create a very nice look.

Red Broomcorn, photo courtesy of Johnny’s Select Seeds

Broomcorn in the Garden

Although broomcorn does have a decidedly agricultural feel, you can still plant it as an ornamental - particularly if you can tuck them behind other plants that will hide the base of their stalks and allow them to shoot up behind to display their large flowering tassels.

We use broomcorn in large clusters at the back of the border to keep them concentrated for biggest impact and the easiest upkeep, but have also used them as a back “screen” to hide a particularly ugly wire fence. Just make sure to watch out for rains and winds, which can knock broomcorn over!

Designing with Broomcorn

Broomcorn is one of our favorite materials to design with, especially in the fall. A single stem of broomcorn can be the filler for an entire arrangement or bouquet.

The way that the tassels fall and drape in an arrangement is particularly wonderful, contrasting well against the more upright and circular forms of flowers like zinnias, marigolds, dahlias and mums. If you cut the seedheads when they are younger (and are still green or yellow) they work well as a vertical accent as opposed to a filler.

If you’re using broomcorn in a mixed arrangement, you may find that you can actually chop up an entire seedhead into several pieces that can be tucked into an arrangement as a lovely filler. If your seedheads are on the smaller side, you can tuck multiple seedheads into arrangements to create motion and allow it to spill over the side.

Broomcorn also plays well with other ornamental grasses, amaranthus, and seedpods, contrasting well with the more fuzzy or spike-like forms of other ornamental grasses like pennisetum or millets, but also works well in contrast to large fluffy flowers like mums and dahlias (it’s like they were made for each other!)

If you’re interested in learning how to design with flowers including how to make bridal bouquets, check out our eBook on the subject “Floral Design for the Flower Farmer”.

Broomcorn, being a grass, has a very long vase life, and can even stay indefinitely if the arrangement is dried. We find that they work well in selling to florists (especially in fall) but also work well for winter dried arrangement sales as well.

If you’re interested in learning more on growing flowers for dried arrangements, check out our eBook on the subject “Growing Dried Flowers”. It’s written for flower farmers, but the information is also helpful for home gardeners as well.