Blue cornflowers -

True blue flowering plants are few and far between but one of the very best blue-coloured plants is the highly attractive and eye-catching cornflower - Centaurea cyanus. Native to Europe, including the UK, it is an annual plant which in the past often grew as a weed in crop fields, hence its common name. Unfortunately it is now endangered in its native habitat, the result of agricultural intensification and overuse of herbicides.

Luckily enough, cornflowers are very easy to grow from seed and so the delights of the gorgeous cornflower can be experienced in your very own garden.  You even get two two sowing seasons every year!

Spring sowing

You can directly sow cornflower seeds outside in their final position from March to April. Cornflowers will need a sunny position on well drained soil. Prepare the seedbed by raking the surface to a fine tilth.

Sow seeds thinly, at a depth of 3mm  in drills spaced 30cm apart. Gently water in with a soft rose and then label so that you know where the seedlings will emerge.

The ground will need to be watered regularly, especially during dry periods. You can expect germination to occur between 14-21 days. Once the cornflower seedlings are large enough to handle, they can be thinned out to 15cm apart to prevent weak growth from overcrowding.

Autumn sowing

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For an early summer show of cornflowers you can start them off under protection from August to September. Fill a seed tray with a good quality compost such as John Innes 'Seed and Cutting' and sow the cornflowers seed on the surface. Do not bury cornflower seed ar it require the presence of light to help initiate germination.

Cover with a very fine sprinkling of compost or vermiculite and gently water using a soft rose. Place the tray inside a heated propagator at a  temperature of 18-23C. Do not exclude light as this helps germination. Alternatively put the seed tray in a clear polythene bag and place in a warm room on a sunny windowsill, but one that does not receive direct sunlight as this can quickly overheat the seedlings and dry out the compost.

Germination should occur between 14-21 days, and when the seedlings are large enough to handle potted on individually into 3 inch pots. Move them to cooler conditions until large enough to be hardened off and kept outdoors. Before the onset of winter move them into cool, light, frost-free conditions before planting out the following spring.

Once in their final positions outside you will need to water cornflowers regularly until the root systems have fully established. To encourage further flowering, deadhead faded cornflower blooms as they arise.

For related article click onto the following links:
How to Grow Cornflowers from Seed

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