The Gardeners Almanac

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Common name: Snapdragon

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Week Numbers




Harden off


Planting out

Powdery Mildew

Pricking out


Seed sowing


Antirrhinums are actually perennials, but are normally grown as half-hardy annuals due to their susceptibility to rust.

They require a sunny position, in well-drained light to medium soil, enriched with well-rotted manure.

Heights vary depending upon variety, e.g.

Dwarfs: can grow from 200-300mm (8"-12") high, Intermediates: 400-600mm (16"-24") Tall: up to 1200mm (4ft).

The spicy scented flowers come in many colours that generally appear from July until early frosts.

The vertical flower spikes, open gradually from the bottom to the top of the plant during the course of the growing season.

A single plant may produce seven or eight blossom spikes in the course of a growing season.

The common name is attributed to the fact that if you squeeze the base of the flower the petals will open and close like jaws.

This attribute can make them a particular favorite of children who like to pinch the tiny individual blossoms and make the dragon's mouth open and close.

Encourage bushy growth by pinching out the growing points when the plants are 75-100mm (3"-4") high

Taller varieties for cutting should be supported in exposed areas.

Remove faded spikes to prolong the flowering period.

A selection of Antirrhinums in the border

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Week 10-12:

Sow the fine seed on the surface of the seed compost, then just cover with silver sand or vermiculite, and germinate at a temperature of 18°-21°C (65°-70°F).

To reduce risk of the seedlings damping-off, add equal amounts (by volume) of river sand to the seed compost to open up the texture.

Germination should take around a week to ten days.

Week 14-16:

When the seedlings are large enough to handle, prick them out into trays/boxes of potting compost and grow on at 12°C (55°F).

Week 17:

Harden off in a cold frame before planting outside after all fear of frost has gone.

Week 22:

Plant out in prepared flower beds/borders 200-600mm (8"-36") apart( depending upon group size.

Antirrhinums prefer a sunny spot, but will perform reasonably well in partial shade.

Week 32:

In milder parts of the country an early sowing of the early flowering types can be made now to flower the following spring