The robust soapwort is not easily intimidated by adverse site conditions. The well-known wild perennial colonizes sandy bank areas, scree slopes or barren wall tops effortlessly and is not afraid of root pressure along sparse trees or hedges. The traditional function as a detergent, which inspired the naming of Saponaria officinals, is now considered obsolete. However, this circumstance in no way reduces the centuries-old reputation as a decorative perennial in rock gardens, natural ornamental plantings and flower borders. Hobby gardeners who became acquainted with the 70 cm high carnation plant no longer know how they ever managed without the flexible soapwort with the distinctive pink-white flowers.


  • Classic plant genus with approx. 30 species.
  • Native to central and southern Europe with 10 species.
  • Growth height 30 cm to 70 cm, maximum 80 cm.
  • Light pink flowers from June to September/October.
  • Narrow, pointed, green leaves.
  • Hardy to – 23° Celsius.
  • Much visited bee and butterfly pasture.
  • Considered to be slightly toxic due to the high saponin content.

The vernacular has given the soapwort other names, such as soaproot, real soapwort, common soapwort and scrubbing herb.


The fact that real soapwort likes to be a pioneer plant on barren fallow land already shows a high site tolerance. Under difficult conditions, however, the wild perennial rarely unfolds the desired bloom. For optimal growth, the following conditions should be met:

  • Sunny light conditions.
  • Sandy, not too dry potting soil.
  • Permeable, humic and rich in nutrients.
  • A potting soil-sand mixture is suitable in the bucket.

Although the washweed prefers a slightly moist soil, it adapts to dry, nutrient-poor locations, such as a gravel bed, the roof garden or the joints of a dry wall. The gardener uses the carnation plant as a practical indicator plant for a neutral to calcareous soil. Even without using a soil analysis, he knows at first glance that plants for acidic potting soil will not thrive here, such as rhododendrons or azaleas.

watering and fertilizing

Saponaria officinalis usually makes do with the natural rainfall, which is quite sufficient for an adequate water supply in the local latitudes.

  • Water common soapwort only during prolonged drought.
  • Regular watering is recommended for tub culture.
  • The supply of nutrients conforms to the condition of the soil.
  • The leaner the substrate, the more often the plant receives garden compost.

If the washweed is cultivated in a planter, it receives a dose of liquid fertilizer every 4 weeks from the 2nd year. Commercial potting soil is usually pre-fertilized to the extent that the supply is sufficient for at least 1 season.

To cut

If a wild perennial, like the soapwort, feels extremely comfortable in a garden, it develops an irrepressible growth potential that goes hand in hand with the tendency to invasive spread. Of course, such concentrated energy can easily be reined in with the secateurs.

Cut out and clear

If the main season is in full swing, withered and out-of-shape parts of the plant quickly spoil the picture or, in the worst case, hinder the growth of new flowers and leaves.

  • Cut out faded flowers every 1 to 2 weeks.
  • In case of strong growth, thin out the soaproot repeatedly.
  • Prune stems with protruding branch-like sticks.

This pruning measure is done in no time at all and pays off: the flowering period is extended and self-sowing, which would be a hindrance, is prevented.

remount cut

If flowering occurs particularly early, pruning opens up the best prospects for a second flowering in autumn. Especially in mild locations, such as the wine-growing regions, the carnation plant sometimes dresses up quite early.

  • Cut back the soapwort to a height of 5 cm to 10 cm.
  • Cut out diseased, stunted foliage in the same operation.
  • Then feed the wild perennial with compost or liquid fertilizer.

If the weather cooperates, Saponaria officinalis will pick itself up and please the eye with another fresh bloom. In regions with a comparatively harsh climate, this aspect of care does not apply, because the washweed only flowers from July and experience has shown that it lasts seamlessly until autumn.

post bloom pruning

Before the winter break, the time is ripe for a radical, low-to-the-ground pruning. So the soaproot is ready to defend itself against frost and snow. The time shifts to a mild day in late winter if self-sowing is desirable.

  • Prune Saponaria officinalis as short as possible.
  • Leave clippings as mulch and fertilizer.

If a garden lover carries out this procedure conscientiously every year, the lifespan of the carnation plant will be extended by several years. In addition, cutting after flowering has proven to be an effective prophylactic against fungal infections of all kinds.


Apart from cutting after flowering, real soapwort does not need protection against frost and snow. In tub culture, however, cold winter winds have almost unimpeded access to the root ball. The walls of the planter alone are not enough to prevent freezing. Of course, a cold house or a frost-free garage offer the best conditions for a successful hibernation. Nevertheless, the hobby gardener is not helpless without such a winter quarters.

  • Put the soapwort in the bucket on a cold-insulating base, like wood.
  • In addition, wrap the container with foil, garden fleece or jute.

If the hobby gardener then layers leaves, straw or fir fronds on the trimmed shoots, the icy cold does not have a surface to attack, even from above. It is important to note that all precautions will be reversed as soon as it no longer freezes. When the strong winter sun shines on the washwort, condensation quickly forms in combination with rising temperatures, which can cause rot.


Once the common soapwort has shown the hobby gardener what it is all about, the desire for more specimens automatically arises. Even a single specimen in the garden is sufficient to raise numerous offspring.


Probably the most uncomplicated form of duplication is in spring or autumn. The only condition is a completely thawed soil.

  • Lift a healthy, strong plant out of the ground with a shovel or digging fork.
  • Split the washwort into two or more segments with a spade.
  • A suitable section has at least 1 or 2 shoots.

The root parts obtained in this way have all the properties of an adult plant. Consequently, they are planted and watered at the new location without further processing.

Note: Before the quite violent division by breaking a spade, it should be tested whether the root ball can be pulled apart by hand.


Propagation is just as easy by using parts of the runners. The prudent gardener does not touch the turnip-like main rhizome. It’s the side rungs that interest him.

  • Dig up the soapwort completely.
  • Shake off the soil and cut off about 5 cm of some of the side shoots that are now visible.
  • Seal the interfaces with charcoal powder and replant the mother plant.
  • Fill small pots with nutrient-poor substrate and insert the root pieces.

The side rungs go into the ground in a horizontal position, just as deep as they were before. It is important to ensure that the fine roots that sprout from the rhizome point downwards. Placed in a bright, warm place, the plant lover regularly moistens the offspring until an above-ground shoot indicates that the underground root system is also thriving.


In contrast to well-known head cuttings, a well-versed hobby gardener takes the basal cuttings as early as spring. Once the new shoots have reached a height of 10 cm, he cuts them off directly at the starting point.

  • Plant each cutting individually in a pot with potting soil.
  • Water regularly throughout spring and summer.

By fall, the basal cuttings are eager to root through the pot. As soon as they have reached their destination, the young plants are mature and are planted out in beds or containers.

Compared to the propagation methods presented, the sowing of soapwort is quite demanding. The cause is the fact that the seeds are cold germs. They will not germinate without an appropriate cold stimulus. Stratification requires an initial phase of 2 to 4 weeks at around 20° Celsius, followed by a further 4 to 6 weeks at 0° to -4° Celsius, before the proven technique of normal germination can begin.


With regard to planting, soapwort differs from most other perennials in only one point. The spread of the long runners should be controlled from the start.

  • Planting time for the soapwort are spring and autumn.
  • Surround the inserted young plants with a root barrier.
  • Alternatively, plant each wild perennial together with a larger pot.

Root barriers consist of very stable geotextile, which is lowered vertically into the ground and closed with special clips at the overlapping ends. Since the material does not rot, it lasts at least as long in the garden soil as the Saponaria officinalis. Weed fleece or pond liner are only rarely able to cope with the increasing pressure of the rhizomes.

diseases and pests

Healthy soapwort that is pruned regularly is less susceptible to disease or pest infestation. On the contrary, it is rather the case that the ingredients, in particular the saponins, are used in biological pest control. The environmentally conscious gardener uses 100 grams of soapwort (a mixture of leaves, flowers and rhizomes) and 1 liter of water to produce a liquid manure against plant lice of all kinds. In a jar with a lid, the solution ferments within 1 week while stirring daily. The sunnier and warmer the location, the faster the process will be. Diluted to 10%, Soapwort Manure naturally controls pests by repeated spraying.

Decorative species and varieties

Saponaria officinalis has served as a parent plant for skilled breeders to create a variety of magical hybrids.

Stuffed Soapwort (Saponaria officinalis ‘Alba Plena’)

  • Growth height up to 80 cm.
  • Double white flowers sprouting from pink buds.
  • Flowering period from June to September/October.
  • Very nice cut flower for the vase.

Summer Soapwort (Saponaria x lempergii ‘Max Frei’)

  • Growth height 30 cm to 40 cm.
  • Carnation-like, pink flowers from June to September.
  • Ideally suited as a lush ground cover.
  • Recommended for spring planting.

Cushion Soapwort (Saponaria ocymoides)

  • Growth height up to 15 cm.
  • Pink flowers in dense mats.
  • Very nice as an underplant in large tubs.

Alpine Soapwort (Saponaria lutea)

  • Growth height 5 cm to 10 cm.
  • Yellow flowers from June to August/September.
  • Thrives even in the cracks of dry stone walls.

Soapwort ‘Bessingham’ (Saponaria olivana x ocymoides)

  • Growth height up to 5 cm.
  • Bright pink flowers with a white throat.
  • Attractive, carpet-forming ground cover.
  • Needs light winter protection.

Imaginative hobby gardeners in particular take advantage of the low-growing varieties by planting flower bulbs scattered between the wild perennials. In this way they set graceful accents that loosen up the appearance.

After centuries of cultivation as a useful and medicinal plant, soapwort is now making a name for itself as a robust yet picturesque perennial. It thrives just as well in the lean, calcareous soil of the rock garden as it does along sun-drenched embankments or in flower borders. The sunnier the location, the denser the dense pile of white, pink or yellow flowers. With the exception of one pruning per year, Saponaria officinalis is content with a little water in dry conditions and some garden compost. Diseases and pests rarely spread to the carnation plant. Rather, real soapwort turns the tables and provides plagued hobby gardeners with the ingredients for an environmentally friendly remedy against lice.

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