How to Grow Zinnias in Central Texas

Zinnias are some of the most gorgeous flowers you can grow in your vegetable garden or flower beds.

From looking at them, you might think the plants are high-maintenance (as most beautiful things tend to be), but zinnias are actually one of the easiest plants to grow from seed—they can even thrive with a little bit of neglect.

If you enjoy having fresh flowers in the house and seeing bright pops of color in your garden, you definitely need to grow zinnias. You’ll also be doing a good dead for the pollinators. Bees and butterflies delight in the long-lasting, showy blooms.

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MY FAVORITE VARIETIES OF ZINNIAS TO GROW

I love the flower seeds from Renee’s Garden and Botanical Interests—so many great heirloom varieties to choose from. You can pretty much find zinnia seeds in whatever shade of fuchsia, peach, purple, orange, yellow, bright red, white, cream, or burgundy you want. You can also choose between double and single petals, bi-colored or one vibrant color.

• Bling bling zinnias – These are zinnia elegans, which is your standard zinnia type, that come in really bold shades of pink, purple, and orange on long stems perfect for cutting.
• Persian Carpet Zinnias – These lovely flowers are made for butterfly gardens, blooming in combos of gold, cream, and burgundy.
• Cactus Flower Blend – These double blooms come in vibrant sunset colors, and the petals are long and feathery.
• Thumbelina Mix – Perfect dwarf zinnia for small spaces or growing in containers. 

Find lots more fun color and petal options here or here.

Pro tip: Look for smaller varieties (the seed packages should say “dwarf” or “container”) if you plan to grow zinnias in a pot or container.

WHEN TO GROW ZINNIAS IN CENTRAL TEXAS

Thanks to our warm climate, we can enjoy the beauty of zinnias for a large portion of the year. Zinnias can be planted in March for flowers by May or June. We get to enjoy these blooms not just through late summer, but all the way through fall, until frost takes these plants out.

In the triple-digit heat of our summer months here in Texas, zinnias will still be thriving while other plants are struggling. That’s because they’re native to southwestern grasslands and can take the heat and even some drought.

You can continue to plant zinnias by seed all the way through about late September for your fall garden. After that, you won’t have enough time to enjoy these plants in your space before frost could come and ruin the zinnia plant party.

WHERE TO GROW ZINNIAS

Zinnias aren’t too picky about their soil, so you can grow them in the ground, in pots or containers at least 12 inches deep (make sure there’s at least one good drainage hole in the bottom), or in your raised garden beds.

Just pick a spot with well-draining soil that receives full sun. Most flowering plants can survive with less sun but won’t bloom as much for you if they get anything under 8 hours of direct sunlight.

If you’re growing tall zinnias, be mindful of not putting them in the front of your beds, where they could quickly outgrow your other plants and cast too much shade.

HOW TO PLANT ZINNIAS BY SEED

Wait to plant zinnias in your garden until all chance of frost has passed. For the Central Texas gardener, that’s around mid-March.

You have two options when it comes to sowing zinnia seeds.

The first method is to sprinkle the seeds over the soil by shaking them from the palm of your hand. This method is an efficient (and fun!) way to plant for in-ground beds, but you might need to come back and thin overcrowded flowers by cutting the base of the plants later. 

The second method is to place the seeds where you’d like them to grow, giving each seed about 6 inches to spread out. I prefer this method for flowers that will grow in my raised beds.

Once you’ve got the seeds scattered or placed, use either your hand or a little hand rake to cover the seeds up with a light layer of soil or compost. 

Water the planting area well to tell the seeds it’s time to sprout.

HOW TO TEND ZINNIA PLANTS

Zinnias are overall super low-maintenance. If you notice pests or powdery mildew on your plants, you can treat them with insecticidal soap or Neem oil as needed. Giving zinnias plenty of space to grow by thinning young plants that sprouted too close together goes a long way toward giving the plants good air circulation and preventing disease.

Your only tasks beyond that will be to water regularly, add fertilizer, and prune. 

Water

These plants really only need moderate water. It’s best to give zinnias one deep soak that will last for several days, if not the whole week, rather than several short waterings.

Feed

Apply a balanced fertilizer every 4 to 6 weeks during the growing season. I like MicroLife Maximum Blooms, which is a slow-releasing liquid fertilizer, but you can use any fertilizers high in potassium and phosphorus.

Prune

Once the first blooms on your plants begin to form, you have a choice to make: Enjoy the current blooms or remove them so that your plants will produce more flowers in the future. I recommend removing them, or “pinching them off”. We didn’t get into gardening for instant gratification, right?

To prune these flowers, simply cut the stem right above a leaf node (a pair of leaves). It might seem a little severe now, but you’ll be rewarded with more blooms later! Zinnias are cut-and-come-again flowers, so the plant will just regrow whatever you take.

You’ll also need to do something called deadheading when blooms are looking a little spent. This just means to prune flowers that are past their prime so that the plant doesn’t spend more energy supporting them. Again, cutting flowers often is the best way to encourage your plants to keep blooming for you.

HOW TO HARVEST ZINNIA FLOWERS

Zinnias typically take about 55 to 65 days to bloom, depending on the weather and the variety you’re growing.

For best results when enjoying zinnias as cut flowers, harvest the flowering stems by cutting at an angle above a leaf node with a clean pair of pruners or scissors. Make sure not to cut any stems that are branching out from the same base—those will soon produce flowers for you.

Take your blooms inside immediately and put in a jar or vase filled with fresh water. Better yet, bring a jar or vase with you to harvest flowers from your garden. Zinnias wilt very quickly after harvest if not placed in vase water. There’s a reason you don’t see these beauties in bouquets for sale very often.

Before our first frost, harvest any remaining zinnia blooms and remove the plants from your garden space.

HOW TO HARVEST ZINNIA SEEDS

Zinnia seeds are incredibly easy to harvest and save for next year. The seeds are those dark gray spears that are hanging out in the middle of an old bloom by the dozens.

You’ll know it’s time to save zinnia seeds from flowers when the blooms are starting to look a little tired, probably around November for our area. Pick only your favorite zinnia plants to save seeds from (you’ll still end up with plenty of seeds).

Take a pair of pruners and cut the stems a couple inches beneath the flower heads. Bring these zinnia flowers inside and hang them upside down to dry for a couple of weeks.

The easiest way to save the seeds once the blooms are completely dry is just to toss the flower heads whole in a jar or baggie. You can also take the time to remove the petals now, but I prefer to keep them. If you’d like to plant zinnias based on their different colors next year, you’ll be able to tell which color the future blooms will be based on the dried petals.

Next spring, you can separate the seeds by rubbing the flower head between your fingers. Plant and start all over!

This is how you can set yourself up for seeds for life by buying just one seed package for each of your favorite varieties. 

ZINNIA FAQs

Is zinnia a perennial plant?

Zinnias are annual flowers, which means they grow from seed, produce blooms, and complete their life cycle within one growing season (whereas perennial plants can live for several years). Even if they could live longer, our first freeze would likely kill them since they’re not frost tolerant.

Are zinnias safe for dogs?

Every part of the zinnia plant—stem, petals, and green leaves—is edible for pets and their humans. You might find the stem a bit chewy, but the flowers make beautiful garnishes for desserts, salads, charcuterie boards, and veggie trays.

Can you start zinnia seeds indoors?

Zinnia seedlings don’t love being transplanted, so it’s best to sow seeds directly in the garden. Save your seed starting indoors efforts and supplies for warm season plants that take a much longer time to grow to maturity, like tomatoes.

Whether you’re going for a more cheerful or elegant look, you won’t regret adding zinnias to your garden space. 

Let us know if you have any other questions about growing zinnias!