For gardeners in hot climates, zinnia flowers make the perfect addition to your garden. Zinnia flowers come in a range of bold colors. From vibrant pink to brilliant yellow, it’s not difficult to find the perfect zinnia flower. Choose a day in springtime, to plant your zinnia seeds. You’ll find you will quickly reap the benefits of having a more visually striking, colorful garden. In today’s guide, we’ll reveal how you can grow and care for zinnias so you can enjoy a brighter, bolder garden throughout the summer months.
Are Zinnias Perennial?
Annual and perennial plants have different care requirements. For instance, annuals require regular replanting, while perennials return year after year, often with minimal maintenance.
If you intend to grow zinnias, you’ve probably asked the question, ‘Are zinnias perennial?’.
Generally, gardeners usually grow zinnia varieties as annuals, meaning that they complete their life cycle within one growing season. However, there are some varieties of zinnias that classify as perennials.
As a perennial, the above ground foliage dies back in winter, but the underground part of the plant lies dormant until warmer weather. This usually happens in springtime, when new above ground growth will emerge. Some zinnia perennials are short lived whereby they weaken and die completely after a couple of years. Whereas other varieties will survive for a few years more.
Examples of perennial zinnias include Zinnia Grandiflora, Zinnia Acerosa, and Zinnia Anomala.
An Exploration of The Different Types of Zinnia Flowers
Below, we’ve explored some of our favorite zinnia varieties.
1. Zinnia Elegans
| Common Name | Zinnia, Common Zinnia, Elegant Zinnia |
| Botanical Name | Zinnia Elegans |
| Family | Asteraceae |
| Plant Type | Annual flower |
| Size | 1-4 ft. tall, 6-18 in. wide |
| Sun Exposure | Full |
| Soil Type | Moist, Well-drained |
| Soil PH | Slightly acidic, Neutral |
| Bloom Time | Late Spring – Autumn |
| Flower Color | Red, Yellow, Orange, Pink, Purple, and White |
| Hardiness Zones | 3-10 (USDA) |
| Native Area | North America and South America |
| Toxicity | Non-Toxic |
Zinnia elegans, or common zinnia, are bushy annual flowers that typically grow between 1-4 ft. tall on upright, branching stems. This variety of zinnia thrives in moist, well-drained soil and full sun. Zinnia elegans come in a range of shades, including red, yellow, orange, pink, purple, and white. They have oval or lance-shaped foliage and make for an excellent fresh-cut flower. Please note that Zinnia elegans is susceptible to powdery mildew, blight, botrytis, leaf spot, and root rot. That being said, good air circulation can help to prevent fungal leaf diseases.
2. Zinnia Grandiflora
| Common Name | Rocky Mountain Zinnia, Little Golden Zinnia, Prairie Zinnia |
| Botanical Name | Zinnia Grandiflora |
| Family | Asteraceae |
| Plant Type | Annual flower |
| Size | 4-8 in. tall, 15 in. wide |
| Sun Exposure | Full |
| Soil Type | Sandy, Loamy |
| Soil PH | Slightly acidic, Neutral, Slightly alkaline |
| Bloom Time | Late Spring – Autumn |
| Flower Color | Yellow, Orange, and Gold |
| Hardiness Zones | 4-9 (USDA) |
| Native Area | Central and Western America, and Mexico |
| Toxicity | Non-Toxic |
Zinnia Grandiflora, or rocky mountain zinnia, is a low-growing perennial flower that usually grows between 4-8 inches tall. These mound-shaped blooms have several multi-branched stems and small, needle-like leaves resembling a shrub. Zinnia grandifloras have yellow-gold and orange flowerheads and are ideal for dry, gravelly rock gardens. Like their annual counterparts, Zinnia Grandifloras thrive in full sun. Please note that Zinnia Grandiflora varieties grow best in sandy, loamy soil.
3. Zinnia Angustifolia
| Common Name | Creeping Zinnia, Narrow-leaf Zinnia, Mexican Zinnia |
| Botanical Name | Zinnia Angustifolia |
| Family | Asteraceae |
| Plant Type | Annual flower |
| Size | 8-16 in. tall, 8-10 in. wide |
| Sun Exposure | Full |
| Soil Type | Moist, Well-drained |
| Soil PH | Slightly acidic, Neutral |
| Bloom Time | Early Summer – Autumn |
| Flower Color | Orange, Yellow, White, Red, and Pink |
| Hardiness Zones | 6-9 (USDA) |
| Native Area | Mexico and Guatemala |
| Toxicity | Non-Toxic |
Zinnia Angustifolia, or creeping zinnia, is a compact, bushy annual that typically grows between 8-16 inches tall. These types of zinnias are drought tolerant, which make them ideal as container plants. In addition, they grow very well in rock gardens and areas with drier soil conditions. Like other varieties of zinnias, Zinnia Angustifolias thrives in full sun and well-draining soil. These blooms also attract pollinators like butterflies. Zinnia Angustifolias come in a range of hues, including orange, yellow, white, red, and pink. What’s more, this variety of zinnias has excellent resistance to fungal diseases such as powdery mildew and leaf spots.
When and Where to Grow Your Zinnias
Ideally, plant your zinnia flowers in areas where they will receive full sun. Although zinnias can flower in partial shade, we don’t recommend planting them in such conditions. Growing zinnias in partial shade can make your blooms more susceptible to disease.
For best results, we suggest planting taller varieties of zinnias at the back of your garden border. Shorter varieties of zinnias grow in mounds, making them a good choice for the front of your garden borders.
Zinnias also thrive just as well in containers, provided that you use well-draining soil.
Additionally, the best time to grow your zinnia flowers is between May and June, when there’s warmer weather conditions and the soil has warmed up.
Growing Zinnias Outdoors
Zinnias are incredibly easy to grow both indoors and outdoors, as highlighted below. By following these simple steps, you will be rewarded with an abundance of colorful flowers in your garden or yard.
Zinnias dislike root disturbance, so we suggest that you sow your zinnia seeds directly into freshly raked, weed-free soil. Ensure that you’ve picked a spot in your garden that receives full sunlight.
Sow two or three seeds in clusters 2 inches apart, making sure that each cluster you sow is 12 inches apart. Lightly cover the seeds with a thin layer (approximately 1/4 inch) of topsoil and water them well. Please note that the aim is to keep the soil moist but not soggy.
Germination usually takes 7-10 days, and when they begin to grow, we recommend covering them with a cloche. A cloche will keep your zinnia seedlings protected against chilly spring evenings and from some harmful flying insects.
When your seedlings have a couple of leaves or are 2 inches tall, thin them out until every zinnia seedling is 12 inches apart. Keep water to about an inch a week, taking great care not to over saturate the soil. In contrast, it is essential not to allow the soil to dry out either. It is advisable to always water only to the needs of the plants
Growing Zinnias in Pots
Growing zinnias in pots differ slightly from growing them outdoors. Here’s how to grow zinnia flowers in pots.
Ideally choose a pot/container with a diameter of at least 12 inches. A pot this size will accommodate the zinnia’s root system. Ensure that your chosen pot has drainage holes at the bottom to prevent waterlogging and subsequent root rot. For moisture control and better air circulation around the roots, we suggest using terracotta pots which are porous and ideal containers for your zinnias.
We recommend sowing zinnia seeds indoors approximately 4-6 weeks before the last spring frost date in your area.
Invest in an adequate seed-starting mix, fill your pot following the instructions, then lightly moisten with water before you sow your zinnia seeds.
Tip: By watering the soil mix before sowing seed, you have more control where the seeds will germinate. If watered after sowing, then the seeds are likely to ‘float’ making it difficult to spread them evenly.
Place your seeds on top of the moist soil, lightly pressing them into the surface until they are about 1/4 inch deep. You can either sow one zinnia seed per pot or space them a few inches apart, depending on the size of your container.
Once planted, cover your seeds with a thin layer of your seed starting mix, as they will need darkness to germinate effectively. Zinnias also need warmth to germinate, so we suggest that you place your pots on a windowsill that receives plenty of sunlight.
If you have insufficient natural indoor light to support a zinnia seed’s growth. Consider using fluorescent grow lights to ensure that your seedlings receive 12-16 hours of bright light per day.
Keep the soil mix moist, gently using a spray bottle to mist the base of the plants whenever the soil starts to get dry.
When your seedlings form two pairs of leaves, they are ready to be transplanted
How to Care for Zinnias
Knowing how to care for zinnias is essential. By meeting zinnia’s care requirements, you will keep them looking healthy, fresh, and beautiful over a longer period. Read on to find out the best way to grow and get the best out of your zinnias.
Light Requirements
All zinnia varieties thrive in full sun. Ideally, it’s wise to plant zinnias in areas where they will receive at least 6 hours of sun each day.
Soil Requirements
Zinnias adapt well to most soil conditions. However, the perfect soil for zinnias is well-draining and rich in organic matter. Additionally, zinnias usually bloom best in slightly acidic to neutral soil. We recommend using a soil pH testing kit prior to sowing your zinnia seeds if unsure of your soil type. Tip: Lime raises the pH of your soil, while sulfur lowers it. Please also note that some varieties may have slightly different soil requirements, such as the Zinnia Grandiflora variety that we discussed earlier.
Water Requirements
Although reasonably drought tolerant, Zinnias will require watering, especially during dry spells. Water regularly, ensuring that your zinnia plants receive at least 1 inch of water per week. However, take care to avoid overwatering to prevent fungal diseases such as leaf spot and powdery mildew.
Temperature and Humidity Requirements
Zinnia flowers do well in daily temperatures of 75°F-85°F. However, zinnia seedlings have slightly different temperature requirements. Zinnia seedlings germinate successfully at temperatures of 70°F and 75°F. Zinnias are not well-suited to humidity, as hot, humid environments encourage fungal diseases. Grown in these conditions, they will need to be regularly monitored.
Fertilizer Requirements
Regardless of where your zinnias grow, they will only need the occasional feeding with a balanced fertilizer as their flowers form. Follow the product instructions to ensure you’ve used the right amount of fertilizer.
Pruning Requirements
Remove any spent zinnia flowers throughout the growing season. It’s best to wait until the zinnia flowers have faded, shriveled, and have started to turn brown.
By deadheading your zinnias regularly, you can keep your flowers tidy and encourage new branching and blooms.
All you need to do is identify which flowers you need to remove. Then, cut the stem beneath each flowerhead, ideally above a leaf node or a new bud.
Growing and Caring For a Zinnia Flower: Final Thoughts
A zinnia flower stands as a testament to endurance, symbolizing long-lasting affection, friendship, and daily remembrance. Zinnia’s bold colors and large flowerheads not only complement their resilient nature but also make for beautiful, bright additions to any garden. By following the advice in our guide, you’ll enjoy fresh and healthy zinnia flowers throughout their entire growing seasons. For more advice on plant care and gardening, check out our blog!
Do zinnias do better in pots or in the ground?
Zinnias thrive when planted in both the ground and in pots. If you have limited space, however, we recommend planting your zinnia flowers in pots.
What happens if you don’t deadhead zinnias?
If you don’t deadhead your zinnias, they will focus their energy on producing seeds instead of new flowers. In this case, you may notice that your zinnias produce fewer blooms and have a shorter blooming season.
What do overwatered zinnias look like?
If you’ve overwatered your zinnia plants, you can expect to see stunted growth, droopy, yellowing leaves, and root rot. You should also expect to see signs of foliar diseases like powdery mildew and leaf spot.
Which zinnia is the most beautiful?
Of course, there isn’t a right or wrong answer to this question; it’s down to personal choice. However, the ‘Benary’s Giant’ (Zinnia elegans) flower is recommended by the Association of Specialty Cut Flowers. They have large, bold, and bright flowers that come in a range of vibrant colors.
