Getting it to bloom

Why won't my Columnae Snow-in-Summer bloom? (and how to make it flower)

Also called Columnae Snow-in-Summer, Snow-in-Summer Columnae (Cerastium tomentosum 'Columnae').

More about columnae snow-in-summer

About Columnae Snow-in-Summer

Cerastium tomentosum 'Columnae' · also called Columnae Snow-in-Summer, Snow-in-Summer Columnae · flowering

Columnae Snow-in-Summer is a selected cultivar of the classic silver-leaved ground cover, forming a tight, non-invasive mat of woolly grey-white foliage smothered in pure white flowers in late spring and early summer. Less rampant than the species, it is ideal for rock gardens, dry walls, and sunny borders where it provides year-round silver texture.

Plant type: flowering

Watch for — Post-flowering tatty appearance: After the main flush of flowers in late spring, the plant can look untidy with faded blooms and sprawling stems. Shear lightly with scissors or shears immediately after flowering to encourage a fresh flush of silvery foliage and maintain a tidy, compact mat. This also reduces self-seeding.

The reasons columnae snow-in-summer isn't blooming

Almost every non-blooming columnae snow-in-summer 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 columnae snow-in-summer 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 columnae snow-in-summer to flower

Maximise sun. Give columnae snow-in-summer 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 columnae snow-in-summer and get the feeding right with the columnae snow-in-summer 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

Columnae Snow-in-Summer 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 columnae snow-in-summer care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Columnae Snow-in-Summer blooming — frequently asked questions

Why won't my columnae snow-in-summer flower?

Columnae Snow-in-Summer 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 columnae snow-in-summer bloom?

Give columnae snow-in-summer 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 columnae snow-in-summer normally bloom?