Growing Rudbeckia for Flower Farmers
Rudbeckia - colloquially known as ‘Black Eyed Susans’ (which I generally don’t use because it’s far too long and is also potentially rude to anyone who may be named Susan) are one of those flowers that doesn’t really get the support and recognition it deserves from floral designers and flower farmers.
I think this is partially due to the fact that rudbeckia don’t bloom usually until the fall - and generally rudbeckia also are known for their bright gold coloration which doesn’t necessarily combine well with other flowers, especially when it comes to wedding color palettes that require softer, more pastel colors.
It’s a shame, because rudbeckia are some of the most hardy and reliable flowering perennials that we have ever grown, and I find their bright, cheery, daisy-like flowers to be a welcome sight in late summer as the days start getting shorter and jewel tones come more into fashion.
Let’s talk a little bit more about this very stalworthy plant!
Rudbeckia are in the Asteraceae family, which also includes coneflowers and asters and chrysanthemums. Not hard to figure out given the form and structure of their flowers (that are also that classic composite daisy shape).
They are technically either perennials or hardy biennials or long-growing annuals depending on how you use them. Landscapers and gardeners usually keep them as perennials, with most flower farmers using them as either hardy biennials or annuals - since they produce the best when planted in this fashion.
Some species of rudbeckia are reliably perennial. Rudbeckia fulgida such as the popular variety ‘Goldsturm’ are a great perennial that comes back year after year to grow and bloom and get bigger with each passing year. Rudbeckia hirta is less reliably perennial for many people - we’ve found the trick to ensuring a perennial nature for R. Hirta varieties is to plant into well-draining soil and mulch well prior to winter starting to ensure the roots don’t freeze over the winter.
Although the typical golden petals of rudbeckia work well into mixed bouquets and seasonal pieces, there are new options for rudbeckia out there that offer much more soft and muted colors and fluffier, different options.
The most popular one right now is ‘Sahara’ with its large, fluffy, triple-flowered forms in colors ranging from dark caramel to golden yellow to light dusty rose to coral to copper and all the combinations in between. The dark velvety centers are wonderful in bridal bouquets and centerpieces to draw the eye, with the centers nestled in the silky velvety petals in the array of soft colors mentioned.
But if soft and fluffy textures aren’t your cup of tea, you should try ‘Chim Chiminee’. Instead of big pillowy flowers, the petals of ‘Chim Chiminee’ are thin and spider-like, reminding me almost of a mum with the same name and will tuck in well to arrangements and design work given their similar coloration with ‘Sahara’.
Of course there are other varieties more in the gold/yellow range as well. ‘Indian Summer’ is the classical dark centered, gold-petalled variety that has massive flowers - some 4” across - that is perfect for using in giant sprawling and cascading installations and arrangements. ‘Prairie Sun’ is similarly large with a lime-green center and large silky yellow petals, while ‘Goldilocks’ is a lovely shaggy double-flowered golden variety as well.
There’s also ‘Cherokee Sunset’ - bronze, coffee, copper, fiery orange, and bicolored double and triple flowers that fit in very well with an assembly of fall blooms, while ‘Cherry Brandy’ features deep red flowers that sink into a velvety black center - an absolutely stunning sight to see.
There are also the spray varieties of rudbeckia, known as Rudbeckia triloba - which includes the varieties ‘Prairie Glow’ and ‘Macau’ that instead of having one large daisy-like flower are instead consist of an entire stem of branching stems covered with small 1” miniature rudbeckia flowers that works great into mixed bouquets, centerpieces and large altar pieces for adding a haze of bright yellow color.
With all the different varieties of rudbeckia, you’re sure to find one that will work for you and the color schemes you’re looking for!
The good news about rudbeckia is the fact that they are very, very cold tolerant. They’re one of the hardiest plants we grow from seed, and so long as you harden off seedlings well they can be planted almost year round (so long as the soil is workable).
It’s also good to note that rudbeckia flower best when they have a period of exposure to cold temperatures. This allows for the biggest flowers and the longest stems due to a process called vernalization - a period of cold (i.e. winter) that signals to the plant that it can get established and put down a good root system that will allow it to flower well the next year. If you start rudbeckia in the spring, you may only get a few flowers and very short stems by the fall - they are best planted in the fall, overwintered, and then allowed to bloom the next year.
It’s this strange scheduling of the planting that makes a lot of flower farmers skip over rudbeckia - their bronze or yellow blooms come right in the beginning of summer and don’t necessarily combine with the light pastel colors that are so popular for flower farmers and wedding designs.
On the other hand, we love the colors of ‘Sahara’ for all those lovely blush and peach and pastel-hued designs, and we just keep the other bolder colors cut back until the fall, when they will rebloom and provide us with plenty of material for fall-colored arrangements.
Growing Rudbeckia
If you’re starting rudbeckia from seed, it’s best to start them in July or August of the year prior to when you want to harvest them for their flowers. This way you’ll be able to grow out your seedlings for a good fall planting that will allow them get established prior to the winter.
Rudbeckia seeds germinate pretty readily - not quite as quick as zinnias or marigolds, but they’ll usually take around 5-10 days to pop up. I find that giving them a cold stratification treatment helps them to germinate more readily and uniformly, but it’s not 100% necessary.
The seedlings are particularly prone to rot, so make sure that you don’t keep them too wet. They also ironically are very prone to drying out too, so ensure that you don’t let them get too hot - they won’t bounce back too readily if they dry out.
It usually takes about two months to get from seedling to a good sized transplant, but once they’re established they are pretty low maintenance, only requiring a little watering and a good feeding of fish emulsion or fertilizer once a month.
Rudeckia originated in the North American prairies, so they enjoy a good clay soil, high humidity and hot temperatures during the summer to grow them large. This is great because so many of us grow in these conditions that aren’t ideal for most other plants - but rudbeckia love these conditions!
They’ll appear as a basal rosette of leaves first, growing bigger and larger until they start flowering and the stems start rising from inside the interior of the plant. It may take a while for the rosette to grow large - they don’t really start taking off until it starts getting hotter, but once they do they will start pumping out a massive amount of flowers.
From just a dozen plants, I harvested two hundred large multi-budded stems during the first flush - each three feet long with a giant 4” flower that went into hundreds of bouquets and centerpieces during the summer months. I got tired of harvesting them and let them go to seed starting in July, harvesting the seed for next year’s plants.
They are pretty hardy and require little care overall, but be careful especially in the fall because the aphids will somehow find them and attach to them in force. Spray off the plants with a sharp stream of water when they start getting too infested.
As I mentioned previously, it’s important to ensure that your rudbeckia are in good raining soil during the winter. If they’re left in standing water for long periods of time, they will rot (especially the ornamental varieties like ‘Sahara’ and ‘Cherokee Sunset’) so ensuring that they drain well is tantamount for their survival. In addition if you get very cold winters (or a long period of multiple freeze/thaw cycles) you may also want to offer them some protection in the form of mulch on top of their crowns.
Some rudbeckias also just aren’t very perennial in nature either, so we always start a flat of new seeds each fall just to ensure we can replenish any plants that don’t come back and fill in any holes that appear.
Harvesting Rudbeckia as a Cut Flower
We harvest rudbeckia when the flowers are just starting to open for the maximum vase life, cutting down at the base of the plant and harvesting the entire stem. Perform the “wiggle” test on the stem to ensure that it’s pretty solid - if the stem is floppy and causes the head to bobble back and forth, it will most likely droop. Sometimes you’ll get some branching or lateral buds - it’s okay to either strip them off or utilize them in your design.
Get your stems into some cool clean water and let them sit overnight before designing with them. Although I do just fine with the stems, note that some people may find the prickly hairs that cover the outside of the stems and leaves to be irritating (in which case you can use gloves to strip off the leaves and arrange with).
We find that our rudbeckia actually last a very long time - I’ve had stems last six weeks when stored in a cool place out of direct sunlight! Nothing crazy either, just stored on a windowsill in clean water. And I am not pulling your leg about it - there’s something about them that allow them to last forever.
Designing with Rudbeckia
Designing with rudbeckia is pretty straightforward - their disc-shaped, daisy-form flowers are great for incorporating into arrangements.
I should state there is a caveat - since they have a very natural center that draws the eye (similar to a dark-centered dahlia or anemone or a sunflower) as a focal point, they are usually used as a very prominent part of the arrangement as a result. Too many may look too busy, and you always run the risk of creating “eyes” if you have two bilaterally symmetrical rudbeckias - so just be careful with them!
‘Sahara’ is by far our most favorite to design with, but they don’t get really long stems until their second year in production. Long stems are easy to arrange with but short stems are bit more difficult - so we tend to use shorter stems for centerpieces and small mason jar arrangements where the stem length is not quite as important as in larger arrangements and bridal bouquets and mixed bouquets.
We tend to use our golden-hued varieties in market bouquets and mixed arrangements - the bright colors pairing well with jewel toned zinnias and dahlias - but we also like using them with sunflowers as a way to repeat the theme of “yellow flower with dark center”. The spray-type Rudbeckia triloba are wonderful when used as filler and especially en masse in large arrangements and installations.
We even use rudbeckia in dried arrangements - the seedheads are a striking dark and structural element, contrasting well when compared to the fluffier, straw-colored materials like grasses, and make for great dried bouquet materials, used in boutonnières and wearables, and are great for incorporating into dried wreaths elements as well.
We’ve even sold the larger seedheads on their own - the massive Rudbeckia gigantea seedheads are like giant five foot spears with black seedheads at their ends look stunning when displayed on their own in a large vase, mixed with gigantic stems of dried okra pods and broomcorn
I hope that this post helped you to get interested in growing one of the easiest, beautiful, unique flowers out there! I love the fact that this flower is also a North American native species and that it does so well here without much maintenance.
Do you grow rudbeckia? Which variety is your favorite? Let me know in the comments below!