What soil does Soapwort grow in?

It tolerates these soils: average garden soil, sandy, calcareous, clay.

Hardy down to -40 °C (USDA zone 3, RHS H7). It gets through winter in every part of the country.

Is Soapwort toxic to children?

Yes, it is mildly toxic to children.

When does Soapwort flower?

Flowering: July–September, pink, white.

How much water does Soapwort need?

Water need: low. Drought tolerance: high.

Soapwort

Saponaria officinalis

Soapwort (Saponaria officinalis) is a perennial. Light: full sun, part shade. Hardy down to -40 °C. Drought tolerance: high. Mildly toxic to children.

Illustration of Soapwort — An illustration of the typical shape of the mature plant, not a photo.

What it's good for, and what it isn't

An old cottage-garden perennial with pale pink or white flowers from midsummer into autumn that are strongly scented in the evening and draw moths. It is undemanding, takes drought and poor, sandy or stony soil and does best in sun; in rich soil it grows lanky and flops. It spreads hard by rhizomes and also by seed, so plant it only where it may run wild, or hold it in check with a sunken root barrier or bottomless tub and by cutting off the spent flowers. The double-flowered forms ('Rosea Plena') spread a little less.

Watch out for

It has no serious pests or diseases; the problem is its spread: within a few years the rhizomes swamp weaker neighbours and it regrows from pieces of rhizome left in the soil, so it does not belong in a mixed border without a barrier. Cut it back after flowering so that it neither seeds around nor flops. Do not plant it beside a garden pond or stream: saponins leaching from stems and roots that trail or fall into the water are poisonous to fish and amphibians.

Key facts

Light: Full sun, Part shade
Water need: Low
Care: Medium
Size after 10 years: 70 cm × 1 m
Hardiness: down to -40 °C
Foliage: Deciduous
Flowering: J F M A M J J A S O N D July–September, pink, white

All details

Group	Perennial
Light	Full sun, Part shade
Size after 10 years	70 cm × 1 m
Ultimate size	0.3–1 m × 0.3–1 m
Hardiness	down to -40 °C (USDA 3, RHS H7)
Soil	Average garden soil, Sandy, Calcareous, Clay
Foliage	Deciduous
Flowering	July–September, pink, white
Water need	Low
Drought tolerance	High
Maintenance	Medium
Root aggressiveness	Low
Suckering	no data
Spreading	High
Distance from buildings	no data
Distance from paving	no data
Litter	not typical
Planting distance	40 cm
For dogs	Mildly toxic (uncertain)
For cats	Mildly toxic (uncertain)
For children	Mildly toxic
Typical price	no data

Toxicity data is for information only. If your pet or child has eaten a plant, contact a vet or a doctor.

Frequently asked questions

Data updated: October 17, 2026 · How our data is made

Appears in these lists

Perennials for part shade Perennials for full sun Drought-tolerant plants Drought-tolerant perennials Drought-tolerant plants for sandy soil Perennials for clay soil Perennials for pollinators Fragrant plants Fragrant perennials

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