If you are looking for a fast-growing plant that will attract beneficial insects to your garden, choose a Mexican sunflower (Tithonia rotundifolia). With the ability to skyrocket upward of 6 feet tall in a single growing season, this annual plant is easy to grow and add cheerful color to the garden.
While not a true sunflower, this native of Mexico, with its fuzzy, coarse-textured foliage in bright green, is a excellent choice as a filler plant to take up garden space and serve as a backdrop for other perennials. The flowers are most often found in warm shades of bright orange and yellow. The blossoms of Mexican sunflowers resemble a large daisy with long, narrow outer petals arranged around a yellow center.
Mexican Sunflower Overview
Where to Plant Mexican Sunflower
Plant a few Mexican sunflowers near your vegetable garden to entice pollinators and beneficial bugs, which can help control potential outbreaks of pests. These plants need a location that receives full sun and has well-draining soil. Plant them at the back of a border or anywhere in the garden you need a tall, fast-growing plant.
How and When to Plant Mexican Sunflower
One of the easiest ways to grow Mexican sunflower is to sow seeds after the last frost in spring. Sow them directly on top of average garden soil because these seeds require sunlight to germinate. In as little as seven to 10 days, you should see signs of germination. At this point, it's best to thin the seedlings to 1 to 2 feet apart, so the mature plants will have enough space to thrive. If you want to get a head start on growing Mexican sunflowers, start them indoors six to eight weeks before the last frost in spring. When the weather warms, they can be transferred out to the garden.
Mexican Sunflower Care Tips
Light
For the most impressive display of flowers, plant Mexican sunflowers in full sun. This also helps keep the plants compact and prevents flopping. In partial sun, plan on staking the plants to keep them upright.
Soil and Water
Ideally, Mexican sunflower should be planted in well-drained soil with moisture levels ranging from average to dry, but Mexican sunflower tolerates poor soil. These plants do not tolerate wet soil or soil rich with organic matter, as they make the plant flop.
Temperature and Humidity
Mexican sunflower grows as an annual in USDA zones 2-11 and can't be overwintered. It can survive temperatures as low as 30°F for a brief period but will incur some damage. Mexican sunflowers like dry weather and don't do well in areas with high humidity.
Fertilizer
After they are established, Mexican sunflowers don't require fertilization. Adding a small amount of organic matter to the planting site at the start of the season is sufficient, but don't overdo it; these plants don't like rich soil.
Pruning
When growing Mexican sunflower plants, plan on deadheading the flowers to encourage late-summer blooms. In tropical climates, deadheading helps prevent potentially vigorous reseeding.
Potting and Repotting Mexican Sunflower
Planting Mexican sunflowers in containers isn't recommended because they grow so large so quickly. If you want to try it, buy a dwarf cultivar, such as 'Fiesta Del Sol', and plant only one or two seeds in an 18-inch or larger terra-cotta container with good drainage. These are annual plants, so repotting isn't needed. Just replant seed each year.
Pests and Problems
Mexican sunflower is deer-resistant and is relatively unaffected by pests. You might see garden slugs if your garden receives a lot of rain. If the sunflowers are crowded and the humidity is high, watch for powdery mildew.
How to Propagate Mexican Sunflower
Mexican sunflowers grow easily from seed, and harvesting seed from an existing plant is simple. Deadhead a spent bloom, pop it into a paper bag, and set it in a warm indoor area to dry. The petals will fall off, leaving only the seed head. Pick up the seed head and rub it between your fingers over a plate or paper towel to cause the seeds to fall out. Store them in a dry area until the weather warms in spring; then, toss them across a garden bed without covering them and water the bed.
Types of Mexican Sunflower
'Goldfinger' Mexican Sunflower
Tithonia rotundifolia 'Goldfinger' has orange blossoms with bright yellow centers and grows to 3 feet tall. Each flower is about 3 inches across. It attracts butterflies and hummingbirds.
'Torch' Mexican Sunflower
At 6 feet tall, Tithonia rotundifolia 'Torch' belongs at the back of the garden bed. Its scarlet-orange petals surrounding orange centers are a well-known attraction for migrating monarch butterflies.
'Yellow Torch' Mexican Sunflower
Tithonia rotundifolia 'Yellow Torch' is the first yellow-flowering Mexican sunflower and a welcome addition to cutting gardens. It stands 6 feet tall and attracts hummingbirds, bees, and butterflies.
'Fiesta Del Sol' Mexican Sunflower
Tithonia rotundifolia 'Fiesta Del Sol' was the first dwarf Mexican sunflower. It handles humidity better than many other cultivars and grows to only 2-3 feet. Its single orange daisies are 3 inches across and are excellent cut flowers. Plus, the plant is basically pest free.
Mexican Sunflower Companion Plants
Canna
Cannas bring tropical splendor to gardens in all regions. These bold plants feature clustered, flag-like blooms in a brilliant color array on tall stems. Recent flower breeding has created canna foliage that is even showier than the petals, with variegated leaf combinations of orange, yellow, and greens that glow in the summer sun. Dwarf cannas are also available for container gardening and other small spaces. Cannas are usually grown from tuberous roots, but some newer varieties can also be raised from seed, with flowering guaranteed for the first year. Cannas provide architectural interest in summer borders, and they also flourish along the damp margins of a pond. If you garden in a climate colder than Zone 9 (7 for the hardier types of cannas), you'll need to dig canna plants up and store them as bare root plants for the next season or overwinter potted specimens indoors. A destructive mottling virus has threatened canna stock in nurseries across the United States, so be sure to buy your plants from a reputable source.
Castor Bean
Plant a castor bean and then stand back. This is one of the fastest-growing giant annuals in the garden, rivaled only perhaps by giant sunflower. By midsummer, you'll have a huge (it can hit up to 20 feet) tropical plant sporting burgundy foliage. Be careful, though. The seeds are extremely toxic. Wait to plant it outdoors after all danger of frost has passed; castor bean hates cool weather and won't grow well until temperatures heat up in summer.
Nasturtium
Nasturtiums are so versatile. They grow easily from seed sown directly in your garden's poorest soil, bloom all season until frost, and are never greedy about food or fertilizer. Nasturtiums are available in either spreading or climbing types. Plant spreading types in large containers to spill over the sides. Plant them alongside wide paths to soften the sides for a romantic look. Use nasturtium to brighten a rock garden or between paving stones. Plant them at the edges of beds and borders to fill in between other plants and add soft, flowing color. Train climbing types up trellises or alongside fences. The leaves and flowers are edible; use them as a showy plate garnish or to jazz up salads.
Garden Plan for Mexican Sunflower
Small Space, Drought-Resistant Garden Plan
This simple garden plan includes tough plants that can withstand dry conditions while still looking lush and colorful. Surround your birdbath with daylilies, penstemon, and bright Mexican sunflowers to create a dramatic display of blooms and foliage.
Frequently Asked Questions
- How are Mexican sunflowers different from regular sunflowers?Familiar yellow sunflowers (Helianthus annuus) are usually taller—up to 12 feet—and many of them have edible seeds. The seeds of Mexican sunflowers, though edible, aren't as tasty as those of common sunflowers; they are somewhat bitter. However, both of these annual plants enjoy the same growing conditions.
Familiar yellow sunflowers (Helianthus annuus) are usually taller—up to 12 feet—and many of them have edible seeds. The seeds of Mexican sunflowers, though edible, aren't as tasty as those of common sunflowers; they are somewhat bitter. However, both of these annual plants enjoy the same growing conditions.
- How long is the Mexican sunflower blooming season?Mexican sunflowers begin blooming in midsummer and bloom continuously until the plant is killed by the first frost.
Mexican sunflowers begin blooming in midsummer and bloom continuously until the plant is killed by the first frost.