Mature size & growth rate

How big does Boissier's Silverbush (Convolvulus boissieri) get?

Also called Boissier's silverbush, Spanish silverbush.

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.

Mature size: 5–15 cm tall and 20–40 cm wide.

Indoor size vs how big it gets in the wild

Boissier's Silverbush is a naturally small plant — it stays shelf- and desk-sized for its whole life, so it never becomes a space problem. Indoors and in a pot, expect 5–15 cm tall and 20–40 cm wide.. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

It grows mostly by adding leaves, offsets or a slightly wider rosette rather than gaining height — the footprint barely changes year to year.

Growth rate and years to mature

Boissier's Silverbush is a moderate grower. Realistically, expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Its feeding profile backs this up: apply a very dilute, low-nitrogen fertiliser once in early spring; this plant naturally grows in impoverished soils and over-feeding causes weak, untypical growth.

Want this turned into the right next pot at the right moment? The pot size calculator and the boissier's silverbush repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast boissier's silverbush grows.

How to keep boissier's silverbush smaller

Good news — boissier's silverbush barely needs managing. If you do want to keep it tidy:

Divide or remove offsets when the pot looks crowded to keep boissier's silverbush to a single tidy clump.
Keeping it slightly pot-bound and easing back on feed naturally caps the size.
Pinch or remove the oldest, tiredest leaves so energy goes into a compact, fresh-looking plant.

How to grow boissier's silverbush bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for boissier's silverbush the accelerators are:

It is already in good light; consistent warmth and a balanced feed in spring and summer are the only levers.
A small step up in pot size every couple of years gives the roots a little more room without triggering a size jump.
Feed lightly through the growing season; this plant simply will not race however hard you push it.

Light is almost always the ceiling. The boissier's silverbush light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When boissier's silverbush outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for boissier's silverbush:

Roots circling the bottom or pushing out of the drainage hole — it wants a pot one size up, not a bigger room.
Offsets crowding the surface so the original plant looks squashed.
Honestly, boissier's silverbush rarely outgrows a room — outgrowing its pot is the only realistic limit.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the boissier's silverbush repotting guide. If you want more of this plant instead of a bigger one, the boissier's silverbush propagation guide turns prunings into new plants.

Boissier's Silverbush size — frequently asked questions

How big does boissier's silverbush get?

Boissier's Silverbush reaches 5–15 cm tall and 20–40 cm wide. when grown indoors. It grows mostly by adding leaves, offsets or a slightly wider rosette rather than gaining height — the footprint barely changes year to year.

Is boissier's silverbush slow or fast growing?

Boissier's Silverbush is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Boissier's Silverbush is a naturally small plant — it stays shelf- and desk-sized for its whole life, so it never becomes a space problem.

How long does boissier's silverbush take to reach full size?

Roughly three to six years to reach mature indoor size, gaining a steady amount each growing season. Light, pot size and feeding move that timeline more than anything else.

How do I keep boissier's silverbush smaller?

Divide or remove offsets when the pot looks crowded to keep boissier's silverbush to a single tidy clump. Keeping it slightly pot-bound and easing back on feed naturally caps the size. Pinch or remove the oldest, tiredest leaves so energy goes into a compact, fresh-looking plant.

How can I make boissier's silverbush grow bigger or faster?

It is already in good light; consistent warmth and a balanced feed in spring and summer are the only levers. A small step up in pot size every couple of years gives the roots a little more room without triggering a size jump. Feed lightly through the growing season; this plant simply will not race however hard you push it.