Zinnias Demystified: Distinguishing Between Annual and Perennial Varieties
Most people know zinnias for their easy-to-grow nature and colorful blooms. But have you ever thought about if zinnias are annuals or perennials? Join us as we answer this question.
About Zinnias
When you think of zinnias, you probably think of bright single flowers that bring pops of color to the garden. But did you know that there are more than 20 different zinnia species?
You can use the term zinnia to refer to any of the plants in the Zinnia genus. All of these plants have “flowers” atop a single stem, and each bloom is composed of ray florets (petals) and disk florets (the flower center).
Zinnias have groups of petals arranged in single, double, or triple layers. Those with single layers of petals appear flat, while those with multiple petal layers can appear almost spherical.
All zinnia species are native to warm regions in the Americas stretching from the Southwest United States to South America. However, gardeners across the world now grow these flowers in their gardens.
Annual vs. Perennial Plants
Annual plants complete their life cycle in one growing season and die the same year they emerge. That means the plants flower, set seed, and die all in one season.
Some examples of annual plants include sunflowers, cosmos, cucumbers, and tomatoes.
Perennial plants live for more than two years. They may complete their whole life cycle in one growing season, or they may only produce flowers in the second, third, or fourth year of life.
Some examples of perennial plants include oak trees, coneflowers, and sage.
Some people treat quick-growing perennials like annuals and replant the plants each spring. This is especially true for tender perennials, which can only survive the winter in warm areas.
Are Zinnias Annuals or Perennials?
It depends on the species!
Many zinnias that gardeners commonly plant are annuals that die each year.
However, some perennial zinnias species can live for multiple years when grown in warm regions.
Factors Influencing Zinnia Perenniality
The main factor influencing perenniality is the species. The vast majority of zinnia species are annuals, but a few are perennials.
Some annual zinnias include the commonly grown Zinnia elegans, as well as Zinnia peruviana and Zinnia angustifolia.
The environment can also impact whether a zinnia grows as an annual or perennial. Perennial species can live for multiple years in warm climates but often die during cold winters. Therefore, gardeners often treat them as annuals in cold climates.
Popular Types of Perennial Zinnias
As mentioned above, there are both annual and perennial zinnia species. Most of these plants are annuals, so listing the perennial species is a bit easier.
If you want to grow perennial zinnias, check out the following species.
Wild Zinnia (Zinnia grandiflora)
This zinnia species is native to the Southwest United States and Mexico, thriving in dry conditions and rocky or sandy soil. It’s a rather small plant, remaining under a foot tall and wide.
The plant produces stunning bright yellow flowers that appear atop branching stems. The plant’s highly branched form makes it appear almost like a small shrub rather than a herbaceous plant.
Another interesting thing about this type of zinnia is that it spreads via rhizomes. That means it’s a great plant to use on steep slopes or in areas prone to erosion.
People may also refer to this perennial zinnia as a prairie zinnia or Rocky Mountain zinnia.
Desert Zinnia (Zinnia acerosa)
Also known as a dwarf zinnia or shrubby zinnia, this perennial zinnia thrives in sunny areas and poor soil. And that makes sense when you realize it’s native to plains and meadows in the Southwest United States.
The plant remains compact, maxing out at around ten inches tall. It also has a highly-branched form, hence the name shrubby zinnia.
It’s a prolific bloomer and produces hundreds of white and yellow flowers during the summer. The white petals droop downward while the bright yellow disc flowers shoot skyward.
Desert zinnias can survive as perennials in USDA hardiness zones 6–10. However, they prefer dry soil and can suffer if the soil remains moist for too long.
Shortray Zinnia (Zinnia anomala)
You may not even recognize this species as a zinnia at first glance! That’s because its ray flowers (aka petals) are very short.
It’s also quite scraggly looking, with a highly branching form and only one flower on each branch.
The shortray zinnia is native to regions in the Southwest United States and Mexico, where it thrives in poor soil and dry conditions. This tolerance means it can be a good choice for hot and rocky areas near mailboxes or beside driveways.
While this zinnia can tolerate hot and dry conditions, it will likely suffer in wet soil. Therefore, you should avoid growing it if you live in an area that receives regular rain.
Are Zinnias Annuals or Perennials FAQs:
Are Most Types of Zinnias Annuals or Perennials?
Zinnias are considered annuals. This means they complete their entire life cycle – from germinating from seed, to growing, blooming, and setting seed – in a single growing season. After this, the plants die off. Despite their single-season lifespan, zinnias are loved for their vibrant, long-lasting flowers that bloom from late spring until the first frost in the fall.
How Do I Determine If My Zinnias Are Annuals or Perennials?
You’ll need to know the species to know if your zinnias are annuals or perennials. If you’re unsure of the species, assume the flowers are annuals since these are more common than perennials.
Do Zinnias Come Back Every Year?
Most zinnias are annuals, so they do not come back each year. That means you’ll want to replant seeds each spring or summer. However, there are a few perennial zinnia species that come back each spring.
Should I Deadhead Zinnias?
Deadheading zinnias, aka removing dead flowers, can help encourage the plant to produce new blooms. However, zinnia plants will continue to produce flowers even if you don’t deadhead the plants.
Can Zinnias Act as Perennials?
In hot climates, where frost is rare or non-existent, zinnias can sometimes survive through the winter and act as perennials, returning year after year. However, this is not the norm and is more of the exception than the rule. Most zinnias are grown as annuals, even in warmer climates.
Do Zinnias Reseed Themselves?
Yes, zinnias can reseed themselves. If the flowers are allowed to go to seed, and the seeds are not collected, they can fall to the ground and germinate the following spring, making the plant a perennial. However, this self-seeding can be unpredictable, and the resulting plants may not always resemble the parent plant due to hybridization.
When Should You Plant Zinnias?
Zinnias are best planted in the spring after the threat of frost has passed. They prefer full sun and well-drained soil. Seedlings are not frost-tolerant, so wait until the weather has warmed before planting.
Do Zinnias Need a Lot of Maintenance?
Zinnias are relatively low-maintenance plants. They are drought-tolerant and generally do well in various soil types. Regular deadheading, or the removal of spent flowers, can keep the plants looking tidy. Be watchful for powdery mildew, especially if the plants are watered from above or planted in crowded conditions.
How Long Do Zinnias Bloom?
Zinnias bloom from late spring until the first frost in fall. They are known for their prolonged blooming period and can provide color in the garden for many months.
Wrapping Up
While common garden zinnias like Zinnia elegans are annuals, a few types of zinnias are perennials. Therefore, it’s essential to know what species of zinnia you’re growing if you want to know whether it’s an annual or perennial.
For more, see our in-depth guide to the best companion plants for zinnias, how to grow zinnias in pots, and how to dry and preserve zinnia flowers.