Getting it to bloom

Why won't my Square-stemmed Pelargonium bloom? (and how to make it flower)

Also called Square-stemmed Pelargonium, Cactus Geranium, Square-stemmed Geranium (Pelargonium tetragonum).

More about square-stemmed pelargonium

About Square-stemmed Pelargonium

Pelargonium tetragonum · also called Square-stemmed Pelargonium, Cactus Geranium · flowering

Pelargonium tetragonum is an unusual succulent-stemmed species from the Western Cape and Eastern Cape of South Africa, immediately distinctive for its four-angled (square), jointed, pale green semi-succulent stems with small, deciduous or semi-deciduous leaves borne only at the joints. It produces cream to pale pink flowers with dark-pink veining in spring and summer. This architectural curiosity wants excellent drainage, a dry winter rest, and bright sun; it is highly intolerant of overwatering, especially when leafless. Toxic to cats and dogs.

Plant type: flowering

The reasons square-stemmed pelargonium isn't blooming

Almost every non-blooming square-stemmed pelargonium 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 square-stemmed pelargonium 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 square-stemmed pelargonium to flower

Maximise sun. Give square-stemmed pelargonium 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 square-stemmed pelargonium and get the feeding right with the square-stemmed pelargonium 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

Square-stemmed Pelargonium 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 square-stemmed pelargonium care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Square-stemmed Pelargonium blooming — frequently asked questions

Why won't my square-stemmed pelargonium flower?

Square-stemmed Pelargonium 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 square-stemmed pelargonium bloom?

Give square-stemmed pelargonium 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 square-stemmed pelargonium normally bloom?