Getting it to bloom

Why won't my Sweet sultan bloom? (and how to make it flower)

Also called Sweet sultan, Musk centaurea (Centaurea moschata).

More about sweet sultan

About Sweet sultan

Centaurea moschata · also called Sweet sultan, Musk centaurea · flowering

Sweet sultan is a fragrant, old-fashioned cottage-garden annual producing large, feathery thistle-like blooms in white, yellow, pink, and lavender, with a warm, musk-like scent that intensifies in the evening. It thrives in full sun and well-drained, moderately fertile soil. Excellent for cutting and highly attractive to butterflies and long-tongued bees.

Plant type: flowering

Watch for — Short bloom period: Flowers flag quickly in hot weather. Succession-sow every 3 weeks from early spring through early summer for continuous bloom. Deadhead diligently to delay setting seed.

The reasons sweet sultan isn't blooming

Almost every non-blooming sweet sultan traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding sweet sultan a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get sweet sultan to flower

Maximise sun. Give sweet sultan the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for sweet sultan and get the feeding right with the sweet sultan fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Sweet sultan flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full sweet sultan care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Sweet sultan blooming — frequently asked questions

Why won't my sweet sultan flower?

Sweet sultan blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make sweet sultan bloom?

Give sweet sultan the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does sweet sultan normally bloom?