Annuals · Butterflies & Bees in the Garden · Garden DIY

Growing Mexican Sunflowers from Seed

I love Mexican sunflowers. Botanically named Tithonia rotundifolia, they add pops of bright reddish-orange color in my perennial border. These Central American natives bloom nonstop once they get going in mid-summer, only surrendering when hit by frost.

Mexican sunflowers are not fussy about their soil as long as it is well drained. They are, however, particular about their sun requirements – full sun is a must. They are sun and heat worshippers and can withstand short periods of drought.

These are not skimpy, wispy, fine-textured plants. They are robust beauties with coarse leaves, often growing more than four feet tall. Plants should be spaced at least two feet apart – three feet is even better. Tallest varieties should be planted in protected areas or they made need staking.

You might need sunglasses to gaze at the flowers of Tithonia rotundifolia. Each of their single flowers – up to 3 inches in diameter on branching stems – sports vibrant color whether they are the classic reddish-orange, orange or yellow.

I plant Mexican sunflowers with tall zinnias and let their bright blooms mingle, tickling each other’s fancy and mine. Butterflies and bees are drawn to the blooms, fluttering from one to another.

There are a few varieties commonly found in local garden centers. Torch grows up to six feet tall and boasts the traditional, reddish-orange flowers. If you love that color but want a shorter plant, choose Sundance. Yellow Torch is as tall as its sibling but features – you guessed it – yellow flowers. If you want a shorter yellow bloomer, try Goldfinger. The blooms of Fiesta del Sol are true orange. This first dwarf Mexican sunflower, rarely reaching three feet, was an All-America Selections winner in 2000.

Mexican sunflowers can’t be planted in the garden until all danger of frost has passed, so why I am writing about them now? I am growing some from seed this year. In past years, I purchased substantial plants growing in 10-inch pots. But at $10 a pot, it was expensive to add nine plants (three groups of three) to my garden.

Instead of shelling out a lot of cash this year, I ordered seeds of Tithonia ‘Sundance’ and thanks to the generosity of Renee’s Garden Seeds, I planted Tithonia ‘Torch’, too.

If you want to grow Mexican sunflowers from seeds, here’s how you do it:

  • Six to eight weeks before the last frost date, plant seeds in pots ½ inch deep and spaced an inch apart in moist, good quality seed-starting mix. I upcycle egg cartons and place two or three seeds in each cell.
  • Cover the pot(s) with plastic wrap to keep their environment humid until seedlings begin to sprout. I use popsicle sticks stuck in the ends of the egg carton to keep plastic wrap above the seed-starting mix. Seeds may germinate in as quickly as a week but can take up to three weeks.
  • When seedlings emerge, move them under lights, keeping the lights just a few inches above the tops of the seedlings.
  • Thin seedlings. Select the strongest plant and remove the others so it has room to grow.
  • Move the lights up as the plants grow.
  • Repot if the plants grow too large. I will surely have to do this because they will quickly outgrow their space in egg cartons. Once they are big enough, I’ll move them into 6-inch pots until they are ready to plant outdoors.

4 thoughts on “Growing Mexican Sunflowers from Seed

  1. Diana,
    I too am growing Tithonia Torch from seed, compliments of Select Seed. What a lovely surprise to receive a “thank you” packet of seeds. I started my Tithonia Torch using the winter sowing method. Several have already sprouted. I was so happy to see your blog. This is my first experience growing Mexican Sunflowers. I am very excited to see the plant in it’s glory.

    Happy Gardening.

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