Everything You Need To Know About Growing Zinnias

Written by Joel SImon in Annuals

Zinnias are annual plants that are native to the Southwestern United States, Mexico, and Central America with about 20 different varieties.

They are an easy-to-grow plant that produces flowers until the first frost creating a mound of blooms throughout the summer with the help of deadheading.

PLANTING ZINNIAS

Zinnias are best planted in hardiness zone 3 through 10 in well-drained soil with a pH range of 5.5 through 7.5.

They can be sown straight into the soil after the last frost or as I prefer they can be started 8 to 10 weeks before the last frost indoors using a cardboard seed starting tray.

Once sown, they take 4 to 7 days to germinate.

They need full sun but they will do fine in partial shade with slower growth and fewer blooms.

For best results, it is recommended before planting or sowing them to till compost into the soil which is known as amending the soil.

This will provide nutrients to the soil, helps with water retention, and will help to keep the soil loose which will make it easier for the roots to grow.

ZINNIAS USES

Zinnias are typically used by gardeners in flower beds, rock gardens, raised garden beds, potting containers, as a border, along pathways, or in mass as a display.

FERTILIZING AND WATERING

Zinnias are best fertilized with a balanced fertilizer such as a 10-10-10 in early spring and again in mid or late summer.

If you prefer an organic approach then you can use a homemade liquid fertilizer.

When applying fertilizer, it is best to apply it between the base of the plant to the tips of the branches. This area of the plant is known as the drip line.

Zinnias require about one inch of water per week around the base of the plant.

Try to avoid the leaves of the plant so the water droplets won’t burn the leaves with the light of the sun.

During times of extreme heat and low humidity, they will need more watering and they should be watered every other day.

MULCHING

Mulching zinnias will help the soil retain water which will reduce the amount of time it takes to water them.

The thickness bed of the mulch is best between 1 to 2 inches thick and may need to be reduced if you live in a moist and rainy climate or if you are getting more rain than usual.

The mulch will also help with weed control which is important because they don’t compete well with weeds

It is best to add new mulch every year as the older mulch breaks down.

BLOOMS

Zinnia Bloom

Zinnias have different-looking blooms depending on the variety such as cactus-flowered, daisy-like, or dahlia-like which is considered a formal look.

Their blooms are available in different colors flowers such as yellow, peach, orange, red, pink, white, and bicolored flowers.

The flowers are known to attract pollinators such as bees, butterflies, and hummingbirds.

When their flowers are spent and allowed to go to seed, they are known to attract finches, sparrows, mourning doves, and dark-eyed juncos.

If you want your zinnias to keep producing flowers then remove the wilted flower before it has a chance to produce seed.

This is called deadheading and with this method, the blooms are not allowed to go to seed therefore the plant will rebloom.

PRUNING

Pruning your zinnias regularly will help to promote new growth and more blooms.

They are best pruned with a sharp pair of gardening shears with at least three sets of leaves above the ground.

PROPAGATING

If you would like your zinnias to return the next season then you can let some or all of the blooms go to seed.

The seed can be collected or allowed to fall to the ground to sprout the following season.

PESTS

Zinnias have a few pests to keep an eye out for that can damage the plant or introduce a disease or virus.

DISEASES

Zinnias that are planted close together can develop mold and mildew issues during times of high humidity.

If this is the case then pruning and preventive measures may need to be taken.

  • Powdery mildew
  • Botrytis blight
  • Blight
  • Bacterial leaf spot
  • Aster yellows

VIRUSES

Plant viruses are caused by pests causing damage to a plant, therefore good pest management is a must.

  • Cucumber mosaic virus
  • Tomato spotted wilt virus

VARIETIES

There are 20 varieties of zinnias available to choose from with some having resistance to plant diseases.

They come in three sizes, spreading ground cover, short, and tall varieties that can reach up to four feet tall.

COLOR CRACKLE ZINNIA

Color crackle zinnias are native to Mexico and are naturally resistant to mildew.

  • Plant size – grows to about 24 inches tall and 14 inches wide
  • Drought tolerant – yes
  • Blooming colors – two-tone flowers that have burgundy petals with white tips and yellow stamen
    • Blooms size – about 2-inches across double blooms
  • Foliage – lance-shaped dark green leaves
  • Deer resistant – yes

BIG RED ZINNIA

Big red zinnias are native to Central America.

  • Plant size – grows to about 39 inches tall and 12 inches wide
  • Drought tolerant – yes
  • Blooming colors – red flowers that fade into a deep orange over time
  • Bloom size – about 6 inches across
  • Foliage – lance-shaped dark green leaves
  • Deer resistant – yes

PEPPERMINT STICK ZINNIA

Peppermint stick zinnias are native to Mexico and they have bicolored blooms with no two being the same.

  • Plant size – grows to about 36 tall and 10 wide
  • Drought tolerant – yes
  • Blooming colors – white and pink bicolored blooms
  • Bloom size – about 2 to 4 inches across
  • Foliage – lance-shaped dark green leaves
  • Deer resistant – yes

ANGUSTIFOLIA ZINNIA

Angustifolia zinnias are native to Mexico.

  • Plant size – grows to about 16 inches tall and 24 inches wide
  • Drought tolerant – yes
  • Blooming colors – orange
  • Bloom size – about 1 inch across
  • Foliage – lance-shaped green leaves
  • Deer resistant – yes

STAR GOLD ZINNIA

Star gold zinnias are a hybrid variety that is a cross between Angustifolia zinnia and elegant zinnia.

This combination brings the best of both varieties of low maintenance, tolerant to humidity and drought as well as resistant to powdery mildew.

  • Plant size – grows to about 14 inches tall and 8 wide
  • Drought tolerant – yes
  • Blooming colors – yellow
  • Bloom size – about 2 inches across
  • Foliage – lance-shaped dark green leaves
  • Deer resistant – yes

DOUBLE ZAHARA YELLOW ZINNIA

Double Zahara yellow zinnias are a hybrid variety that is resistant to mildew issues.

  • Plant size – grows to about 18 inches tall and 18 inches wide
  • Drought tolerant – yes
  • Blooming colors – yellow
  • Bloom size – about 2 and a half inches across with double blooms
  • Foliage – lance-shaped dark green leaves
  • Deer resistant – yes

Joel SImon

As a kid, Joel found enjoyment in caring for the many houseplants he grew up with, learning how to transplant them safely, cloning them, and more. At about the age of 10, he wanted to see if he could sprout an orange seed from a store-bought orange and ended up using it as a science experiment in a school project. Throughout the many years of gardening, he has helped many friends and family set up their food and botanical gardens. After years of caring for plants, he was talking with other gardeners and discovering old methods of farming and botanical gardening. Joel has decided to share his knowledge for others to enjoy as he has for many years.

Recent Posts