Getting it to bloom

Why won't my Crown of Thorns bloom? (and how to make it flower)

Also called Crown of thorns, Christ plant, Christ thorn, Crown-of-thorns (Euphorbia milii).

More about crown of thorns

About Crown of Thorns

Euphorbia milii · also called Crown of thorns, Christ plant · flowering

Crown of thorns is a spiny, succulent flowering shrub from Madagascar prized for near year-round bracts in red, pink, salmon, yellow or white. It loves bright direct sun, dries out between waterings and shrugs off neglect. The milky sap and thorns make it toxic and unfriendly to curious pets and children.

Plant type: flowering

Watch for — Few or no flowers: Almost always insufficient light. Move to the sunniest window or supplement with a grow light; the plant needs several hours of direct sun to bloom well.

The reasons crown of thorns isn't blooming

Almost every non-blooming crown of thorns 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 crown of thorns 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 crown of thorns to flower

Maximise sun. Give crown of thorns 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 crown of thorns and get the feeding right with the crown of thorns 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

Crown of Thorns 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 crown of thorns care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Crown of Thorns blooming — frequently asked questions

Why won't my crown of thorns flower?

Crown of Thorns 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 crown of thorns bloom?

Give crown of thorns 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 crown of thorns normally bloom?