Are there any flowers that ask nothing of you but give you so much in return? Let me introduce you to the unicorn of the garden world: zinnias. Bright, cheerful, drought-tolerant, and apparently immune to the kind of neglect that kills lesser plants. Zinnias cope just fine in this heatwave weather, too.
But the best news? Zinnias are among the fast-growing, heat-loving blooms that you can still start from seed in July.
No wonder, then, that Zinnias are seriously having a moment right now. A recent Instagram video from Brianne Martin capturing their riotous summer color is a great reminder of exactly why. In the caption, she wrote, “They’re one of the easiest cut flowers to grow – and once you plant them, you’ll probably grow them every year.”
Why Everyone Is Growing Zinnias Right Now
This extreme heatwave weather we’re experiencing this summer is probably the number one reason why zinnias are having a moment right now. And as forecasts predict the hot weather looks set to continue all summer, we are all turning away from thirsty hydrangeas and astilbe to choose tough, heat-tolerant flowers that practically grow themselves.
Joe DeFrancesco from Farmer Joe’s Gardens, whose family has farmed in Connecticut for four generations and who grows zinnias commercially, puts it plainly: “Zinnias are having a moment because they deliver maximum impact with minimum fuss.” His farm grows several varieties – State Fair Mix, Thumbelina, and Cut and Come Again – and he calls them “probably the most reliable summer annual we offer.”
Megan Proska, Associate Vice President of Horticulture and Collections at the Dallas Arboretum, where zinnias are trialled every year in one of the most rigorous plant testing programmes in the country, agrees. “Zinnias continue to stand out as a summer annual because they’re fast-growing, heat-loving, and bloom continuously with minimal care. They thrive in full sun, tolerate Texas heat extremely well, and perform beautifully in landscape beds, in containers, and cut flower gardens.”
And with over 200 varieties, there really is the right zinnia for every garden, whatever zone you’re in.
There’s also the pollinator angle, which is driving part of their popularity as people become more considerate about planting to help their local wildlife. Shelby Lucero of Growing Spaces, who grows zinnias both inside greenhouses and outdoors, has noticed something interesting about colour preference. “Butterflies are most attracted to red, pink, and orange zinnia colours – these colours appear to glow to butterflies. Purple varieties attract bees more effectively because this colour signals a high pollen source to them.”
Hummingbirds and hummingbird moths are fans too, which is the kind of garden wildlife list that makes you want to go and plant some immediately.
And while pollinators love zinnias, deer hate them. “Almost all of our outdoor flowers get decimated by the local deer population,” Lucero says, “but deer don’t touch the zinnias.” If you’ve ever watched a deer methodically destroy an entire border, you’ll understand why this is practically a selling point on its own.
Because they’re annuals, completing their life cycle in less than one year, zinnias are extremely quick to grow, too, with some varieties speeding from seed to flower in as few as 60 days.
And did I mention that zinnias make great cut flowers?
How to Grow Zinnias Well
It’s super-easy to grow zinnias, even if you’re a beginner gardener. Proska’s advice is straightforward: “Sow zinnias in warm soil with plenty of airflow, water at the base of the plant, and deadhead regularly to encourage flowering. Succession sowing every few weeks also helps extend the display.”
DeFrancesco adds that their drought resistance, once established, is genuinely impressive. “They actually prefer lean soil and can handle neglect better than most flowers.” Which is basically the dream!
For cut flowers specifically, he recommends planting tall varieties like State Fair Mix and pinching out the first blooms to encourage bushier growth. Lucero’s cutting technique is precise: “Determine the desired stem length and cut them at an angle with sharp shears just above a set of leaves.” These Fiskars Pruning scissors on Amazonare just the job.
Common Zinnia Mistakes To Avoid
Both overwatering and over-fertilizing are all too easy if you’re growing zinnias in a bed among other more demanding flowering plants. “The biggest mistake new gardeners make is overwatering – zinnias hate wet feet and will develop powdery mildew,” says DeFrancesco. Proska flags the same issue from another angle: watering the foliage rather than the base is a fast route to powdery mildew later in the season.
Giving zinnias room to breathe rather than growing plants too closely together is another good way to avoid powdery mildew, as good airflow is the best defence. If you live in a humid zone where powdery mildew is more common, then there’s an even easier solution. Profusion zinnias have been bred to have strong resistance to this problem. They’re self-cleaning, too, which means they don’t need deadheading, as new blooms continuously replace old ones. Eden Brothers sell a good number of Profusion zinnias including ‘Profusion Apricot’,, Profusion Red-Yellow Bicolor’, ‘Profusion Double Fire’ and ‘Profusion Double Hot Cherry’.
On fertilizer, Lucero is direct: “Zinnias do best in poor soil conditions. Excess nitrogen will result in more foliage growth, but fewer blooms.” Less really is more here.
The Best Zinnia Varieties to Grow Now
Proska’s recommendations come with serious credentials – all of the following have won an Arboretum Approved or Flameproof award in the Dallas Arboretum’s trial programme, and seeds of many are available from Eden Brothers: Zydeco Series, Profusion Series, Zesty Series, Benary’s Giant, Magellan Series and Zahara. Lucero’s favorites, all available from Botanical Interests, are Cactus Flower Blend, Cut and Come Again and California Giants.
My personal favorite is Benary’s Giant Wine, with tall, fully double blooms in a deep magenta. Seeds are available from Eden Brothers.
Can’t decide? Sow this Zinnia Crazy Blend from Amazon, with 12 different varieties.
Pick one, sow somewhere sunny, keep seeds and young seedlings watered until the plants are grown roots deep enough to find moisture for themselves, and your zinnias will do the rest.
