Getting it to bloom

Why won't my Boissier's Silverbush bloom? (and how to make it flower)

Also called Boissier's silverbush, Spanish silverbush (Convolvulus boissieri).

More about boissier's silverbush

About Boissier's Silverbush

Convolvulus boissieri · also called Boissier's silverbush, Spanish silverbush · flowering

Convolvulus boissieri (synonym C. nitidus) is a dwarf, cushion-forming evergreen sub-shrub native to rocky, sun-baked mountain slopes of southern Spain. It produces large, gleaming white to pale pink funnel-shaped flowers against dense, silver-silky foliage, making it a sought-after plant for alpine gardens, troughs, and rock gardens. It requires near-perfect drainage and full sun; it is particularly intolerant of winter wet at the root crown. It is not documented as toxic to pets.

Plant type: flowering

The reasons boissier's silverbush isn't blooming

Almost every non-blooming boissier's silverbush 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 boissier's silverbush 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 boissier's silverbush to flower

Maximise sun. Give boissier's silverbush 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 boissier's silverbush and get the feeding right with the boissier's silverbush 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

Boissier's Silverbush 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 boissier's silverbush care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Boissier's Silverbush blooming — frequently asked questions

Why won't my boissier's silverbush flower?

Boissier's Silverbush 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 boissier's silverbush bloom?

Give boissier's silverbush 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 boissier's silverbush normally bloom?