We have been growing cornflowers at our house for many years now, it is plant that puts on a great show with its flowers, flowers for a long time, easy to grow, tough and is great for attracting beneficial insects. Blue cornflowers are important to Katelyn and I as its one of the flowers we had planted for our garden tea before we got married.
When to Plant Cornflowers
Cornflowers can be grown all year round, just avoid sowing seeds and transplanting through hot or cold weather. The best time to sow seeds are March to April and August to September.
Where to Grow Cornflowers
Cornflowers love between 4-6 hours of sunlight a day. Cornflowers can grow up to 90 cm tall, so we prefer to locate them towards the rear of a garden bed so that it doesn’t block other plants. I quite like having them planted crowded together providing a mass ball of colour.
How to Propagate Cornflowers
Cornflowers can only be grown from seeds, and they are very easy to propagate from seeds. We prefer to start our cornflowers off in seedling trays or small pots. Cornflowers take 7-14 days to germinate and germinate best when soil temperatures are between 15-18 degrees. Another option is to purchase seedlings from a nursery, depending on how many you want this maybe a cheaper option.
A lot of our cornflower seedlings come from self-seeded cornflowers, however the problem is with self-seeded cornflowers you cannot guarantee their colour, when they will come up and if they will come up at all. You can also just scatter sow the seeds directly into the garden bed, however this is harder to control the environment and soil temps.
How to Transplant Cornflower Seedlings
Cornflowers are ready to be transplanted once they have received their first true leaves and are between 5-10cm tall. When transplanting we like to add some compost, manure and a organic slow release fertilser to the area which we are transplanting the cornflower seedlings into. We then water them in thoroughly before making sure there is good layer of mulch around the cornflowers.
When do Cornflowers Flower?
Cornflowers should flower in 70-80 days from germination. This can be affected by the weather, if it’s been a hot summer they may flower earlier and if it’s been a cold winter later.
How Care for Cornflowers
Cornflowers don’t require a lot attention at all, but to extend their flowering season and encourage new flowers, cut old flowers off just above there sets of leaves. If you are in a windy location your cornflowers may need staking otherwise, they may fall over, we have not had this issue.
Can I Save the Seed From My Cornflowers?
The seed can be saved from your cornflowers which means you will have seeds year after year. To save the seed wait until the flowers are faded and dry. Remove from plant and place in a dry envelope. Store in a cool dry place until your ready to sow the seed.
Common Problems When Growing Cornflowers
Cornflowers are an easy plant to grow, and we have not had any issues with growing them at all other than snails and slugs trying to decimate them after being transplanted. Here are some issues you may come across.
Snails and Slugs
We have only found this to be a issue when the plants are young. We recommend in going out with a light at night to check your plants to make sure there a no snails and slugs on them while they are young. Here is more information on how to control snails and slugs.
Aphids are small sap sucking insects which you will find on new shoots and the underside of leaves. If in small numbers, you can just squish them with your fingers or wash them off with a jet of water. If their numbers are high, we recommend in spraying with a horticultural oil or potassium soap.