How to Grow Cornflower (Bachelor’s Button): Easy Winter Blue
Cornflower, also sold as bachelor’s button, is the easiest true blue flower you can grow in a Pakistani or North Indian winter. Sow the seed straight into a sunny bed or pot in October or November, keep it on the dry side, and you’ll pick blue buttons from about February to April. Leave a few heads at the end and it often sows itself for next year.
The short version
- Botanical name: Centaurea cyanus
- Sow on the plains: October to November, directly in place
- Karachi: November to December
- Hills: March to April
- Pot: 10 litres (10 to 12 inch) for 3 plants
- Sun: 6 hours
- Petals: edible, if grown without sprays
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Is cornflower an annual or a perennial?
Annual. NC State’s extension toolbox describes it as a hardy, low maintenance cool season annual that does better in cooler climates and reseeds easily. NC State also says that in mild winter areas you sow it outdoors in autumn, which is exactly our plains situation.
How do I grow cornflower from seed?
- Mix: ordinary garden soil with a little sand and a handful of compost. It doesn’t need rich soil.
- Sow 2 or 3 seeds per spot, about 1 cm deep, 20 cm (8 inches) apart.
- Water once well, then keep just moist. Sprouts usually show in 1 to 2 weeks.
- Thin to the strongest seedling per spot at 3 to 4 leaves.
- Support: in a windy spot, push in twiggy sticks around the group in January. NC State notes plants flop without support or in too much shade.
Cornflower can be raised in trays (see our seed tray guide), but direct sowing is simpler and the seedlings grow stockier.
Seed or nursery seedlings for a beginner?
Seed. It’s big enough to handle, cheap, quick to sprout, and rarely sold as nursery plants anyway. This is one of the best first seeds for a child to sow, with an adult watching.
Sowing and bloom by zone
| Zone | Sow | Bloom |
|---|---|---|
| Karachi | November to December | February to March |
| Lahore, Faisalabad, Delhi | October to November | February to April |
| Multan, Sukkur, Bahawalpur | October | February to March |
| Islamabad, Peshawar | October | March to May |
| Hills | March to April | June to August |
How often should I water cornflower?
Less than you think. In the ground, every 6 to 8 days in winter; in pots, when the top 3 cm is dry, usually every 3 to 4 days. Frost nights don’t bother it. From March, water every 2 days in pots and expect plants to fade once days pass the mid 30s. Feeding: skip it, or one compost top dressing in December.
Let a few heads go to seed
From mid March, stop deadheading two or three plants. Their heads dry into little brushes full of seed that drop into the bed. Come October, seedlings pop up on their own, and you only need to thin them. NC State notes deadheading controls spread, so do it on the rest of the plants for longer flowering and leave just a few for next year.
Why is my cornflower not flowering?
- Shade: under 5 hours gives thin, floppy stems.
- Rich soil: lots of leaves, fewer flowers.
- Late sowing: January sowing on the plains rarely flowers well before heat.
- Crowding: unthinned clumps compete and bloom poorly.
Pests and problems
NC State notes no serious insect or disease problems, with possible wilt, rot, rust, aphids and mealybugs. Rinse aphids, remove rusty or rotten stems, and avoid wet soil. Sprays are rarely needed; if you use one, read the label, wear gloves, and keep kids and pets off until it dries. Remember that sprayed petals are no longer edible.
Are cornflowers good for bees and a vegetable bed?
Yes. Bees and other pollinators visit the open flowers through late winter, when little else is in bloom on many roofs. A short row along the edge of a palak or onion bed brings pollinators close to your food plants, and it costs a single packet of seed. Keep it on the sunny side of the bed so it doesn’t shade young greens, and pull extra self sown seedlings in October before they crowd the vegetables.
Can I eat cornflower petals?
Yes, NC State lists the flowers as edible. Pull the blue petals off and scatter them over salads, raita or rice for colour. They don’t taste of much. Eat only flowers you grew without sprays, and only a garnish amount.
Nursery or florist cornflowers may have been sprayed, so don’t eat those. Anyone with a daisy family pollen allergy should test a single petal first, or skip eating them. In the ground, cornflower spreads easily and can become weedy; deadhead most plants if you don’t want it everywhere. If anyone has swelling or breathing trouble after eating flowers, get medical help immediately.
How do I save cornflower seeds?
Let a head dry fully on the plant until it opens into a brown brush, usually April. Snip into a paper bag, rub gently, and the slim seeds with a tuft fall out. Dry a week and store in an envelope. They keep for the next season easily.
Grow it or skip it?
Grow it. It’s the simplest blue flower for a winter garden, works in pots or the ground, feeds bees, and gives a few edible petals. Skip only if your space is shady or you dislike plants that self seed. A good pairing is larkspur for height, though keep that one away from children. Mix advice is in our potting mix guide, and more in Phool aur Paudhe.
Cornflower, answered
How do I grow cornflower from seed?
Sow 1 cm deep directly in a sunny spot in October or November, keep the soil just moist, and thin seedlings to 20 cm apart.
When should I sow cornflower seeds in Pakistan?
October to November on the plains, November to December in Karachi, and March to April in the hills.
How long does cornflower take to flower?
Usually around three to four months, so an October sowing tends to bloom from February.
Is cornflower the same as bachelor’s button?
Yes, both names refer to Centaurea cyanus.
Do cornflowers come back every year?
Not from the same plant, as it is an annual, but it self seeds easily, so new plants often come up the next autumn.
Can cornflower grow in pots?
Yes, three plants fit a 10 to 12 inch pot in full sun. Stake them lightly if the spot is windy.
Are cornflowers edible?
The petals are edible as a garnish if the plants were grown without sprays.
Why are my cornflowers falling over?
Too much shade, rich soil or wind. Give full sun, skip fertiliser and add twiggy supports early.