Snapdragons (Antirrhinum) – The Complete Guide

With snapdragons (Antirrhinum), sometimes also called dragon flowers, we associate a perpetual summer, bursting with colorful splendor.

Thanks to the different growth heights, these charming summer flowers adorn the window box. The long-stemmed beauties stand out as backdrops in the perennial bed or vase decoration.

If you know your stuff, you can guide these nostalgic gems safely through the winter season. In the following, we provide all the information you need about successful cultivation.

Planting Snapdragons Correctly

For snapdragons, the starting time for planting is no earlier than mid/late May, as the young plants are extremely sensitive to cold.

Place the potted root balls in a container with soft water. Then proceed to prepare the soil in the sunny location.

According to the desired number, dig small planting pits at intervals of 8-10 inches (20-25 cm). Mix the soil compost with horn shavings.

Plant one specimen at a time so that the root ball is just below the surface of the soil. Please do not tread the substrate, but only press it with your hands to water abundantly.

Care Tips for Snapdragons

Direct your snapdragons through a blooming summer season with this simple care program:

  • When the soil has dried out, water with soft and normal water alternately.
  • In the bed, fertilize every 3-4 weeks with compost; in the pot, treat every 2 days with liquid fertilizer.
  • Do not fertilize from September on, if wintering is planned.
  • Cut off withered flower stems to a hand’s breadth above the ground to encourage a repeat bloom.

Do you cultivate a hardy variety or is your garden located in a region with mild winters? If so, take a chance on overwintering your snapdragons.

Keep the leaves on the plant until spring and spread a thick layer of foliage, fixed with fir fronds. After pruning, potted flowers should preferably be placed in frost-free winter quarters.

Which Location is Suitable for Snapdragons?

Snapdragons develop their summer flowering abundance in a sunny, warm and sheltered location. They also tolerate semi-shaded locations but this will lead to reduced flower volume.

The majestic varieties are best kept in a wind-protected place so that their long stems are not knocked over. Snapdragons make no special demands on the quality of the soil.

The flowers thrive in any good garden soil that is nutrient-rich, humus-rich, and, above all, well-drained.

The Correct Planting Distance

You will draw enchanting garden pictures with snapdragon if you arrange the flower in small groups. Because of its slender shape, we recommend a planting distance of 10-14 inches (25-35 cm), regardless of the expected height of growth.

An exception is the majestic Antirrhinum majus, which assumes a corresponding girth at a height of up to 4 ft (120 cm). Here we advise a planting distance of 20-24 inches (50-60 cm).

What Soil Do Snapdragons Need?

In order for snapdragon to spread its strong root system unhindered, it is important to have loose, humus-rich, and well-drained soil.

In waterlogged sites with compacted clay soil, you will wait in vain for the lavish flowering candles. A neutral to slightly acidic pH of 5.5 to 6.5 is advantageous for the vitality and abundance of the flowers.

For cultivation in pots and window boxes, we recommend rhododendron soil or a mix of potting soil and bog soil. Enrich the soil with lava granules, pumice, or perlite respiration flakes.

When is Flowering Time?

From June to October/November the mighty flower candles put themselves in the scene.

Cut off withered stems just above the ground to encourage the growth of new flower spikes. Leave the ground-hugging foliage because it will supply the post-bloom.

Now your summer flowers will gratefully accept a portion of compost or liquid fertilizer to sprout again with fresh vigor.

Pruning Snapdragons Properly

Cut off a wilted flower corolla in time before the plant begins the energy-sapping growth of capsule fruits.

When doing so, place the scissors just above the basal leaves from which the next floral column will rise.

Allow the autumn flowers enough time to self-seed before cutting them to a hand’s width above the ground.

This will ensure a continuation of the floral display next year should a harsh winter derail plans for perennial cultivation.

Then cut off the retracted leaves in early spring so that the next generation of snapdragons can flourish unhindered.

Watering Snapdragons

Thanks to their strong root system snapdragons are well equipped for short periods of drought. This stress should nevertheless be the exception.

Constant soil moisture is beneficial for growth and flower abundance. Water the flowers when the soil has dried.

In the pot and balcony box, experience shows that this is necessary more often than in the bed, where Mother Nature participates in the water supply with downpours.

Ideally, water alternately with soft and normal water. This way, the lime content in the substrate does not accumulate to undesirable heights.

Fertilize Snapdragons Properly

In the bed, organic fertilizers are excellent for adding nutrients. Work compost, horn shavings, bark humus, guano, or horse manure lightly into the soil with a rake every 3-4 weeks from June to September. Afterward, follow up with watering.

In pot culture, we recommend the administration of liquid fertilizer at 2-week intervals.

Diseases

With their lavish flowers and leaves, snapdragons are a welcome prey for the fungal spores of mildew. However, the disease can cause actual damage only when the plant is weakened by neglect in care.

In the early stages of infestation, a home remedy that has proven effective is a mix of water and fresh milk in a 9:1 ratio.

In the advanced stage, cut off the infected plants and unceremoniously sow directly in the bed. Germination progresses rapidly in the middle of the summer.

Wintering

Competent breeders have taken the hobby gardener’s desire for perennial snapdragons to heart and developed hardy hybrids, such as ‘Pretty in Pink’ or the sturdy F1 mix ‘Sonnet’.

Provided your garden is in a winter-mild region or the plants are in a niche with a mild microclimate, most Antirrhinum majus is suitable for perennial cultivation.

Here’s how to maneuver the flowers healthily through the cold season:

  • Before the first frost, cut off the wilted flower stalks down to the ground level foliage.
  • Mound a 8 inch layer of fall foliage on the root disc, covered with coniferous brushwood.
  • Cut off the leaves only in early spring.

Pots and window boxes with snapdragons resettle in a frost-free winter quarter. This could be an unheated stairwell, a bright basement room, or a garage.

Here, water the plants occasionally to prevent the root ball from drying out.

Propagating Snapdragons

The flowering corms, which are not cut back, produce clearly visible capsule fruits in the fall, bulging with seeds.

Collect these, remove the seeds, and after a short drying period store them in a screw-top jar in a cool cellar until spring.

This is how propagation by sowing succeeds:

  • Between February and March, sow the seeds on moist sowing soil.
  • Do not cover the light sprouts, but only press them with a board.
  • Place them in a heated greenhouse in a semi-shaded location.
  • At 68-77 °F (20-25 °C) germination starts within 10-21 days.

The strongest seedlings are pricked out into 3-4 inch pots when they have at least 2 pairs of leaves.

Now it is important to place the little snapdragons a little cooler and gradually accustom them to full sunlight.

In mid/late May, plant out the offspring into the bed, container, or window box.

Snapdragons in a Pot

Cultivation in a pot is just as uncomplicated as for snapdragons in the bed.

Suitable substrates are rhododendron soil or a mix of standard potting soil and bog soil. Add a few handfuls of perlite or lava granules for good permeability.

A few shards of clay above the bottom of the pot will prevent damaging waterlogging.

How to care for Antirrhinum properly:

  • Water with soft and normal water alternately as soon as the soil has dried.
  • Fertilize with liquid every 2 weeks from June to September.
  • Cut off wilted flower corms down to basal foliage for repeat blooming.

Before the first frost, carry the cut-back plants to a frost-free winter location. At temperatures between 41 and 50 °F (5 and 10 °C), water much less and do not apply fertilizer.

Is Snapdragon Poisonous?

Its visual appearance already signals its botanical relationship to numerous speedwells. Thus, snapdragon is not completely harmless in terms of its ingredients.

In fact, the summer flower is classified as a mildly poisonous plant, as various glycosides and alkaloids are found in the plant sap and in the seed heads.

Therefore, it is better to refrain from cultivation within the reach of small children and pets.

Beautiful Snapdragon Varieties

In the following list we have collected some particularly beautiful varieties of snapdragons.

  • Twinny Appleblossom: Magnificent Antirrhinum majus with double, pink-white apple blossoms; growth height 10-12 inches (25-30 cm).
  • Pretty in Pink: Rare, hardy snapdragon in bright pink for border and vase; height of growth 20-24 inches (50-60 cm).
  • Royal Bride: Majestic, white flowering noble variety that exudes a beguiling fragrance; growth height 31-35 inches (80-90 cm).
  • Black Prince: Compact Antirrhinum nanum that displays its deep red flowers in the border and container; height of growth 18 inches (45 cm).
  • Rembrandt: Picturesque noble variety that delights with bicolor orange-gold flowers; growing height 18-20 inches (45-50 cm).
  • Bronze Dragon: With almost black leaves and purple-white marbled flowers, a feast for the eyes; growth height 12-14 inches (30-35 cm).
  • Circus Clowns: Colorful mixture of medium snapdragons for bed and balcony; height 16-18 inches (40-45 cm).
  • Lucky Lips: Tightly upright large snapdragon with pink-white flowers; height of growth 31-35 inches (80-90 cm).
  • Madame Butterfly: Charming, double-flowered, long-stemmed premium variety, ideal for the vase; growth height 28-31 inches (75-80 cm).
  • Chinese Lanterns: Innovative breeding of hanging snapdragons for hanging baskets and window boxes; growth length up to 20 inches (50 cm).