Sowing and Growing Snapdragons (Antirrhinums)

Snapdragons, or antirrhinums, are one of those flowers that really reward patience. They take their time to get going, but once they do, they give weeks of colour and wonderful, long stems for cutting. For us, they’re an essential early-summer flower, bridging the gap between spring and the height of the cutting season.

This is how I sow and grow snapdragons here, along with a few lessons learned along the way.

Why sow snapdragons early

Snapdragons are half-hardy annuals and naturally slow to develop. Because of this, they need a long growing season to really perform well. I sow mine in January, which gives them plenty of time to grow into strong plants and flower at the start of summer.

You can sow them in autumn and overwinter young plants, but they will need protection, a greenhouse or cold frame is essential. We don’t tend to do this, simply because looking after lots of tiny seedlings all winter can be quite a commitment. Starting them early in January works well for us and fits into the rhythm of our growing year.

How I sow snapdragons

Snapdragon seeds are tiny, so gentle handling is key.

• I sow into open seed trays filled with damp, fine compost.

• The seeds are sprinkled evenly over the surface, they need light to germinate, so they’re not covered with any compost.

• I then lightly spray with water to settle the seeds into the compost and make sure they have good contact with the surface.

• A clear lid is placed on the tray to keep humidity in.

  
  

The trays go onto a heat mat to germinate. As soon as I see signs of germination, they’re moved straight into the greenhouse.

Madame Butterfly bronze with white

After germination

Once seedlings are up, I keep the lids on initially, removing them gradually as the seedlings develop. This helps maintain moisture early on, then improves airflow as the plants grow, which is especially important for keeping them healthy.

In very cold or frosty weather, I protect young plants with lids and horticultural fleece. They’re resilient, but steady conditions help them establish without stress.

Pricking out and growing on

Last year, I pricked my snapdragons out in early March and grew them on individually in small pots. They stayed undercover while they put on steady growth, becoming good-sized, sturdy young plants.

They were planted out in early May, once the risk of hard frost had passed.

By mid-June, they were flowering and they did really well.

Our favourite varieties for cutting

Our go-to snapdragons for cutting are Potomac and Madame Butterfly. Both are reliable performers and produce strong, tall stems that hold well in arrangements.

This year we’re growing:

• Madame Butterfly bronze with white, ivory and cherry bronze - soft, warm tones with beautifully ruffled petals

• Potomac Lavender

• Potomac Soft Pink

These varieties consistently give us the stem length and flower quality we need for cutting.

Supporting the plants

I add a mesh support once plants are established. This keeps stems upright and straight and makes a huge difference to the quality of the first flush.

The first crop is usually the best, with long, strong stems and well-formed flower spikes. We often get a smaller second crop later in the summer, especially if plants are cut back and cared for well.

Feeding and general care

Snapdragons aren’t particularly greedy, but they do benefit from some extra nutrition.

• Start feeding once plants are established and flowering begins.

• A balanced liquid feed every 2 to 3 weeks is usually enough.

• Avoid over-feeding with nitrogen, which can lead to lots of leafy growth and fewer flowers.

Regular cutting also helps keep plants productive and encourages fresh growth.

Preventing rust

Snapdragons can be prone to rust ( a fungal infection), especially later in the season.

To reduce the risk:

• Give plants good spacing and airflow

• Avoid overhead watering where possible

• Remove any affected leaves promptly

• Keep plants healthy with steady watering and light feeding

  
  

Good airflow is the biggest factor. This is another reason I’m careful about removing lids early and supporting plants properly as they grow.

A final thought

Snapdragons ask for patience early on, but they repay it generously. Sowing in January gives us flowers at the very start of summer, which feels just right.

They’re not the quickest or easiest flowers to grow, but they are dependable, beautiful and hardworking - and once you’ve grown your own, shop-bought stems never quite compare!

Madame Butterfly ivory