Getting it to bloom

Why won't my Cosmos sulphureus 'Klondike' bloom? (and how to make it flower)

Also called Klondike Sulphur Cosmos, Dwarf Orange Cosmos (Cosmos sulphureus 'Klondike').

More about cosmos sulphureus 'klondike'

About Cosmos sulphureus 'Klondike'

Cosmos sulphureus 'Klondike' · also called Klondike Sulphur Cosmos, Dwarf Orange Cosmos · flowering

A compact, heat-loving annual prized for vivid orange and gold semi-double daisies that bloom from early summer to first frost. 'Klondike' is more compact than tall sulphur cosmos, thriving in poor, lean soils and full sun. Drought-tolerant once established, it self-seeds readily and draws bees, butterflies, and hoverflies all season.

Plant type: flowering

Watch for — Few flowers, lots of foliage: Caused by rich soil or feeding. Stop fertilising and grow in lean soil to restore prolific blooming.

The reasons cosmos sulphureus 'klondike' isn't blooming

Almost every non-blooming cosmos sulphureus 'klondike' 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 cosmos sulphureus 'klondike' 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 cosmos sulphureus 'klondike' to flower

Maximise sun. Give cosmos sulphureus 'klondike' 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 cosmos sulphureus 'klondike' and get the feeding right with the cosmos sulphureus 'klondike' 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

Cosmos sulphureus 'Klondike' 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 cosmos sulphureus 'klondike' care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Cosmos sulphureus 'Klondike' blooming — frequently asked questions

Why won't my cosmos sulphureus 'klondike' flower?

Cosmos sulphureus 'Klondike' 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 cosmos sulphureus 'klondike' bloom?

Give cosmos sulphureus 'klondike' 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 cosmos sulphureus 'klondike' normally bloom?