In Phoenix, Arizona, where I grew up, zinnias were just about the only flower you could see blooming in July and August. Therefore, I hated them! I longed for flowers that were lush and the exotic, softly fragrant and intricately formed. I wanted the flowers I saw in California when I visited relatives every summer. I scorned zinnias!
But now that I’ve lived and gardened in California for thirty years, and especially now that I’m growing cut flowers as a business, I have a new appreciation for zinnias, because they’re tough and tolerant of heat and neglect, but most of all because they’re bloom machines!
Here are my tips for growing zinnias.
Select the right variety for you – see the discussion below.
Grow from seed to get more for your money. Floret and Johnny’s Seeds are good sources.
Plant seeds in trays or directly into the garden, but either way, plant in full sun.
Zinnias can take heat, but they can’t stand cold, so don’t plant until the weather is warm.
Use lots of Sluggo until plants are larger – snails love baby zinnias.
Be generous with water for small plants. Once they’re established zinnias can be more drought-tolerant, but they won’t flower well if you’re too stingy with water.
Pinch! See my post on the subject here. Pinching will double your flower yield.
And here’s a short list of zinnia varieties. You’ll find even more in catalogs and online.
‘Profusion’ If size doesn’t matter to you, and if you don’t need them as cut flowers, then choose Profusion. These are shorter plants with exceptional resistance to mildew. They crank out blooms for months and take care of themselves. The Profusion series offers several colors: Fire, White, Cherry, Gold and Apricot.
‘Benary Giants’ If you want the biggest flowers, go for the Benary Giant series. My personal favorite is Benary’s Giant Carmine Rose – it’s a showstopper. Others in this series are Salmon Rose, Orange, Scarlet, Wine, Lime and White. The green and white versions have smaller blooms and aren’t as floriferous. Unfortunately, Benary’s Giants can get mildew. Fortunately, this usually happens late in the season and I’ve never seen it affect the flowers.
‘Oklahoma’ If you need better resistance to mildew, try the Oklahoma series. These are medium height plants, flowers on the small side, but they’re prolific, and they’re wonderful cut flowers. Lots of good color choices, including Scarlet, Gold, Pink, Ivory and Yellow.
‘Cupcake’ Similar to Oklahoma - small but good as cut flowers, resistant to mildew.
‘Queen Lime’ If you’re drawn to more unusual flowers, try the Queen Limes. I have to confess, I’ve never had any luck with these, but they’re all the rage on Instagram, so someone must be succeeding!
‘Envy’ A large green zinnia – I’ve had trouble growing that one too.
‘Zowie’ A bicolor in brilliant orange and yellow.
‘Senora’ A beautiful cactus-form.
‘Zinderella’ These zinnias have a puffy dome of short petals; they’re also called “scabiosa-flowered.” In catalog photos they’re cuter than kittens! But even though I can grow them, I can’t get them to look like those pictures. Apparently, they need just the right conditions and zero stress to form those lush tops, otherwise they make single flowers, which are fine, but not what we want from our Zinderellas.
Clockwise from top left: Benary's Giants in a mixed bouquet with small white Tanacetum; Benary's Giant Carmine Rose; a mixed bouquet with zinnias; a small bouquet with Oklahoma Ivory zinnias and orange Tithonia.
Now about mildew … Although it’s sure to appear if you grow zinnias, it doesn’t affect the flowers. I use organic gardening practices, so no chemical sprays for me. Neem oil is allowed, and it works fairly well, especially if you start using it early in the season, before mildew is well established. Sometimes I find it’s better to remove the plants mid-season and replace them with fall blooming plants such as asters. I lose some zinnia blooms that way, but the garden looks better and I’m less annoyed.
If you love zinnias and want to learn more, check this blog post from Erin Benzakein of Floret.