Polsters in gardens or on slopes are very popular among hobby gardeners. The hardy mountain sandwort, which forms a lush white bloom between May and July, is particularly suitable for this. The evergreen plant is also suitable as a grave plant and, due to the easy maintenance, can also be used for green roofing. There is also no need for special care in winter. It can also be cultivated in a bed with other perennials and sets beautiful accents in the flower bed or rock gardens.
Profile of mountain sandwort:
Scientific name: Arenaria montana
Plant family: carnation family (Caryophyllaceae)
Other names: –
Sowing time: April, needs cold to germ
Planting time: March to April
Flowering period: May to July
Location: sunny to partially shaded
Soil quality: stony to sandy, low in nutrients, humus poor
These information are for temperate climate!
Use in: roof greening, borders, grave planting, planters, dry walls, rock garden, potted garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 4 (-34 °C / -25 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of mountain sandwort
Plant order, origin and occurrence of mountain sandwort
The mountain sandwort (Arenaria montana) is a petite, but surprisingly robust little perennial. They are home to the mountainous regions of southwestern Europe, from the Pyrenees to Spain to Portugal and it also occurs in Morocco. Sandworts belong to the plant family of the carnation family (Caryophyllaceae). The mountain sandwort is one of about 300 species that are particularly common in the cold to temperate regions of the Northern Hemisphere.
Characteristics of mountain sandwort
The perennial and evergreen sandwort forms dense polsters that can be up to 30 centimeters (12 in) wide. In height, the plant does not reach more than 10 centimeters (4 in).
The lanceolate dark green leaves of the sandwort sit opposite on the stems. They are entire and with a length of 1 to 3 centimeters (0.4 to 1.2 in) very small.
From May to July the mountain sandwort forms bowl-shaped flowers, which are formed from five snow-white petals and enclose a yellow center. They are up to 2.5 centimeters (1 in) in diameter. They always stand together in several evenly branching inflorescences, so-called dichasias. At the time of flowering, the leaves are barely visible under the dense flower pads.
As is common for the carnation family, mountain sandwort forms capsule fruits that contain the brown to black seeds.
Mountain sandwort – cultivation and care
The mountain sandwort needs at least three hours of sun a day, but ideally the chosen location has up to half a day of sunlight. In the other hours of the day, the perennial tolerates partial shade to shade. However, the selected location must not be too dark.
The sandwort has a low humus and nutrient requirement, but also thrives on normal garden soil. Good soil permeability is essential for its well-being. Older plants also get along very well with dry soils, calcareous substrates are not a problem.
The best time to plant is spring, March or April, so that you can enjoy the flowers immediately afterwards. Since the ground cover does not tolerate waterlogging and generally prefers to be dry rather than too wet, drainage must be created. To do this, stones or gravel are placed on the bottom of the planting hole so that the excess water can drain off better and does not accumulate in the ground. The planting distance should be about 30 centimeters (12 in).
Tip: In the first weeks after planting, the mountain sandwort needs more water. A regular watering and keeping the soil moist is therefore important in the first few weeks so that the plant can grow. Only then can it tolerate the phases of drought.
The mountain sandwort is usually propagated by division, which should also be carried out every few years due to the care. This also prevents the upholstery from expanding too much and, above all, the roots from becoming too compact. If the plants are not divided, this compaction can cause the roots to wither because they have no more space. Therefore, such a division is not only important for the propagation of the plant, but also for general care. The division is therefore carried out as follows:
- divide every two to three years for care reasons
- the ideal time is spring before budding
- can also be divided in autumn
- dig out the plant carefully
- remove dead and old roots
- remove weak shoots as well
- divide the root ball into pieces of equal size
- replant the new plants
Advice: If one misses to divide the plant every few years it will age. No or only stunted new shoots are formed, flowers also fail to appear. It is therefore important that the stone herb undergoes this rejuvenation.
It is also possible to grow from seeds. However, it should be noted that Arenaria montana is a cold germ and that it is best cultivated from April on outdoors.
The mountain sandwort can withstand dry periods once it has grown well after planting. Immediately after planting, however, the soil should be kept moist, with waterlogging absolutely to be avoided. After that, watering can be done moderately or not at all, because the sandwort tolerates a longer dryness better than if the soil is too moist to wet for a long time.
The easy-care perennial also requires little fertilizer. So it is sufficient if the planting soil is enriched with compost once a year in spring. Plants cultivated in a bucket should, however, be supplied with liquid fertilizer every two to four weeks.
Even if the mountain sandwort is a ground cover, the plant should still be cut regularly. Especially if sick, old or weak shoots show up, these should be removed immediately. The withered flowers must also be cut regularly. In this way, a second blooming in autumn can be promoted. Prune the plant before winter to prepare it for the cold season. The green shoots and leaves remain even over winter, they are also winter green.
If the mountain sandwort was cultivated in a bucket, it does not necessarily have to be repotted. However, this perennial, like its conspecifics in the garden bed, should be allowed to rejuvenate by division every two to three years. If the plants are removed from the bucket for this purpose, the substrate can also be replaced and the plant can be given new, fresh soil.
Diseases and pests
The mountain sandwort is completely insensitive to plant diseases and pests when planted at the right location, even from snail feeding the wild perennial is spared.
The perennial is completely hardy. If the mountain sandwort was cut back in the fall, it does not require any further precautions for winter, because the root ball remaining in the ground is hardy. Water additions or fertilizers can also be avoided in winter. To protect the new shoots that form in spring from frost, a little foliage can be placed over the rootstock. However, this should not be an exaggeration, because large piles of wet leaves can promote the formation of mold.
Use in the garden
The sandwort is a typical shrub for rock gardens that can be easily combined with other polster-forming species such as rockcress, moss phlox and saxifrage. Wall or pavement joints can also be planted with the graceful upholstery. It is also pretty as a border for paths or green roofing. When using it as a grave decoration, one should note the sun-seeking of the plant.
Frequently asked Questions
Do I have to protect my mountain sandwort from winter and frost?
Special protection for frosty days is usually not necessary, as the perennial is frost-resistant down to -20 °C / -4 °F. Only old and dried shoots should be removed one last time before winter. Otherwise, the ground cover is winter green and thus also offers a colored eye-catcher to a dreary winter garden.
Why does my mountain sandwort need to be divided regularly?
The ground cover is one of the perennials that wither if they are not rejuvenated regularly, every two to three years. At the same time, this is a division and thus an increase in the number of plants. In this process, the plants are removed from the ground, all old roots and shoots removed and then divided into several plants by taking the roots apart with your hands. This prevents the roots from growing into each other too much and thus atrophying the sandwort overall.
What is the ideal location for my mountain sandwort?
A sunny location is ideal, where at least three hours of sunshine a day are granted. Otherwise, the white flowering ground cover grows well in many places. It can be cultivated in a rock garden as well as on a green roof or as a slope attachment. In addition, it can be cultivated together with other plants.
Can sandwort chock out other plants? I have sandwort as ground cover under my lavender plant and the lavender is not doing well this year. Didn’t know if it had anything to do with the sandwort.
Not sure. Generally, you don’t plant these types together. Lavender can grow quite big, and sandwort grows pretty dense as a ground cover. Maybe your lavender is getting old?
I left my to dry out and now it looks like it’s dieing. Should I prune it or what should I do?
Maybe it helps to rejuvenate the plant by dividing the root ball. This is best done in March or April. Cutting off dead roots and dry shoots ensures that the small parts of the plant grow successfully. A small amount of compost also supports this process. Please let me know if this works.