Zinnia cut flower display

How to grow zinnias

Find out all you need to know about growing zinnias, in this practical Grow Guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Sow
Sow

Do not Sow in January

Do not Sow in February

Do Sow in March

Do Sow in April

Do not Sow in May

Do not Sow in June

Do not Sow in July

Do not Sow in August

Do not Sow in September

Do not Sow in October

Do not Sow in November

Do not Sow in December

Plant
Plant

Do not Plant in January

Do not Plant in February

Do not Plant in March

Do not Plant in April

Do Plant in May

Do Plant in June

Do not Plant in July

Do not Plant in August

Do not Plant in September

Do not Plant in October

Do not Plant in November

Do not Plant in December

Flowers
Flowers

Plant does not flower in January

Plant does not flower in February

Plant does not flower in March

Plant does not flower in April

Plant does not flower in May

Plant does not flower in June

Plant does flower in July

Plant does flower in August

Plant does flower in September

Plant does flower in October

Plant does not flower in November

Plant does not flower in December

Zinnias are mostly annual plants, popular because of the colourful, daisy-like flowers. Native to Mexico, there are 18 species and hundreds of cultivated forms, which are grown as annual bedding plants. Flowers come in vivid colours from red, orange and deep pink to green, with a lovely long flowering season from summer to the first frosts. Zinnias are perfect for filling gaps in the border and also work well in container displays. Long stemmed varieties make great cut flowers.

Advertisement

Zinnias thrive in hot, dry conditions, so grow them in well-drained soil in a sunny border. Single-flowered varieties are attractive to pollinating insects, particularly hoverflies.

Follow our practical guide to growing zinnias, below.


Where to plant zinnias

Planting zinnia plants
Planting zinnias

For best results grow zinnias in well-drained soil in a sunny, sheltered spot.


How to plant zinnias

Zinnias can be sown indoors from February until April, or sown outdoors directly into the soil in May. If sowing in trays or modules, make sure you use free-draining compost, so seedlings don’t suffer from dampness.


Propagating zinnias

It’s best to grow zinnias from fresh seed every year, also to ensure the colour mix of your chosen cultivar. But if you want to save seed for fun or thriftiness, you can select a few blooms to leave for harvesting. When the flowers have faded, you’ll find the seeds in just behind the base of the petals. Store the seeds in an airtight container until you are ready to sow as above in spring.


Zinnias: problem solving

Zinnias can be prone to powdery mildews, mould and leaf spot, but don’t have any problems with pests.


Looking after zinnias

Pick zinnia flowers regularly to keep more coming, and apply liquid feed through the growing season.


Zinnia varieties to try

Zinnia elegans 'Queen Red Line'
Zinnia elegans ‘Queen Red Lime’
Advertisement
  • Zinnia tenuifolia ‘Red Spider’  – a compact zinnia, with wide-spaced, spidery petals, growing to a height of 60cm
  • Zinnia haageana ‘Soleado’ – known as the Mexican zinnia, this species has smaller leaves, making it more tolerant of hot dry conditions and winds. ‘Soleado’ bears masses of single orange flowers on strong, stems. Plants are easy to grow, resistant to rain and flower until the first frosts
  • Zinnia elegans ‘Queen Red Lime’ – the red flowers have lime-green tips to each petal. Grows to 60cm
  • Zinnia elegans ‘Envy’  – with unusual semi-double, lime green, dahlia-like blooms on long stems, this is more tolerant of shade than other zinnias. It also makes an excellent cut flower
  • Zinnia elegans ‘Orange King’ – a tall-growing zinnia, growing to 75cm, the flowers are showy, semi-double orange blooms. It’s ideal for using to fill gaps in the border, and also works well in container displays
  • Zinnia elegans ‘Purple Prince’ – a very tall-growing zinnia, up to 90cm, bearing striking double flowers in magenta with a lime green centre. It is perfect for growing in informal, naturalistic situations with grasses and other tall-growing annuals