Sagina

( sa - JEE - nuh )

At-A-Glance Information

This delicate perennial is commonly called Irish Moss, Scotch Moss, or Pearlwort and forms a dense, green carpet. Species do well in full sun or partial shade, and needs regular water to perform well in the landscape. They can take foot traffic, and are commonly planted as a lawn replacement, groundcover, or in between stepping stones. It is an ideal plant for rock gardens, where it softens the edges of large stones, spills over boulders, or fills crevices. Sagina can also be grown in containers on patios or balconies.

Sagina Species and Varietals

The genus Sagina is a member of the plant family Caryophyllaceae, and includes 20 to 30 distinct species. The plants in this genus are related to those in Silene (Campion), Agrostemma (Corncockle), Saponaria (Soapwort), Gypsophila (Baby's Breath), and Cerastium (Chickweed). The best growing zones for Sagina species include USDA hardiness zones 4-8. To find your zone, click here: Zone Map.

Sagina apetala (Annual Pearlwort, Dwarf Pearlwort)
This species is native to Europe, and has naturalized in many areas worldwide. It is commonly seed growing in disturbed habitats, sidewalks, and roadsides. It produces a threadlike stem a few inches long that can grow erect or decumbent. Flowers are white to cream colored. This species is weedy in many areas of the globe, but is not considered invasive.

Sagina decumbens (Trailing Pearlwort, Western Pearlwort, Pearlwort, Eastern Pearlwort)
This species can form an erect or trailing plant with stems that reach up to over 6 inches long. Stems and leaves are green, and small spring and summertime flowers are white to yellow-cream. The species is generally considered a weed in lawn areas and gardens.

Sagina procumbens (Procumbent Pearlwort, Bird's Eye Pearlwort, Matted Pearlwort)
This species is native throughout Europe and has naturalized in many areas around the globe. It is considered a minor weed of urban areas and lawns, preferring moist habitats. These ground-hugging perennials reach up to 6 inches tall when mature, and produce green stems and foliage. Flowers are delicate and green to purple tinged white. This species is considered highly invasive on sub-Arctic islands such as Marion Island.

Sagina subulata (Heath Pearlwort, Awl-Leaf Pearlwort, Scottish Moss, Irish Moss)
This species is native to a region of Europe that spans from Iceland down through Spain and eastward to southern Sweden and Romania. It prefers to grow on sandy or dry, gravelly soils. These plants are low, prostrate growers reaching up to just 1-2 inches tall when mature. They spread mossy carpets to 12 inches wide, rooting where nodes make contact with moist soil. Plant 6 to 12 inches apart for best coverage. Cultivar 'Aurea' produces bright chartreuse to neon yellow-green foliage and tiny white blossoms.

Caring for Sagina

Sagina, or Pearlwort, should be planted in full sun to partial shade; ideally, these flowers like to get between 6 and 8 hours of direct sun each day for best performance and flowering. They appreciate afternoon shade when temperatures are at their peak to avoid burning foliage, especially in hot or dry climates. Ensure that soil is well-draining, lean in nutrients, and has a pH of between 5.5 and 7.0 (slightly acidic to slightly alkaline). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, Pearlwort species appreciate consistently moist soils, needing frequent irrigation during hot or dry periods to remain healthy. Ensure that these plants are not left in soggy conditions, however, as this will quickly cause issues with root rot.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. To prune, trim back dead, brown, or sprawling runners in early spring using sharp, clean shears. Overgrown or patchy mats can be taken down to about an inch above the soil level to encourage a flush of new growth. These plants can be divided, but do not necessarily need to be for their ongoing health. If clumps become patchy and develop dead centers, which can happen after a few years in the ground,

Caring for Sagina in Containers
Sagina plants are wonderful in the ground, but can also be grown in containers, where they spill over sides and create a mounding effect. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. Fill with a well-draining potting mix amended with organic material and perlite, and top with a layer of mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Sagina plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot. At repotting time, plants can also be divided, which should occur every 2 or 3 years to prevent pots from becoming overcrowded. For instructions on how to successfully divide a Sagina plant, see the Propagation section below.

Propagation

Saponaria, or Soapwort, can be propagated by division, cutting or seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division or cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant, especially if you are propagating a hybrid cultivar. To propagate your Soapwort, follow the instructions below:

Propagating Saponaria by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Saponaria by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
In early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-4 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new plant.

Propagating Saponaria by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.

Sagina seed pods are small globose dry capsules which split open to release dust-like seeds. Each contains dozens to hundreds of microscopic seeds.

Sagina seeds are exceptionally tiny, dust-like, and dark tan to brown in color.

Problems and Pests

Certain species of Sagina are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Sagina plants are typically considered quite resilient, though they can be susceptible to developing issues with the following pests and diseases in the landscape from time to time: