Sempervivum Arachnoideum Care “Cobweb Houseleek”

Sempervivum arachnoideum
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Sempervivum arachnoideum, also known as Spiderwort, has flowers that are typically purple-red or pinkish in color. Spiderwort is a perennial plant that’s native to Europe, Asia, and North America. It grows best in areas with full sun exposure, but it can grow just about anywhere as long as the soil is well-drained. Sempervivum arachnoideum requires very little water once established.

Spiderworts are a genus of Sempervivum in the Crassulaceae family. Sempervivums are succulent plants that store water in their leaves, stems, and root system to enable them to grow when conditions become dry. They have a variety of shapes, sizes, and colors with some being more hardy than others.

Spiderworts can be found growing all over the world in areas such as North America, South America, Asia, and Europe. The most common Sempervivum arachnoideum is also known as “Jointleaf Spleenwort” or “Houseleeks” because it has small foliage that generally grows close together like fingers on your hand

They are perennial flowering plant that belong to the Crassulaceae family and can be found in a wide range of environments from high mountains to low valleys. It has been observed growing on rocky alpine slopes, screes, stream banks, or walls with little soil. They thrive well in sandy soils and drought conditions but does not tolerate frost.

Origin and description

Sempervivum arachnoideum

Sempervivum arachnoideum is a small succulent that typically grows in clumps. Its leaves are rosettes and can grow to be about an inch tall, although they typically only grow up to three-quarters of an inch tall. The plant’s flowers bloom from June through September and range in color between red and pink, sometimes with white edges.

This plant is native to the Pyrenees, Alps, and other mountain regions in Europe. It typically grows at altitudes between four thousand feet and twelve thousand feet above sea level on rocks or walls exposed to strong winds. The plant prefers mineral soil and will grow in full sun or partial shade, but can also tolerate growing under an overhang.

Sempervivum arachnoideum propagation

Sempervivum arachnoideum

Propagation is simple for this plant. In the spring, you can fork off a small section of new growth and toss it into the ground to establish its own root system. You’ll have an instant clump that will grow quickly once established! It’s also common to collect seed from Sempervivum arachnoideum in late summer if you wanted to grow it from seed.

Propagation of Sempervivum arachnoideum is done by seed or offsets. Seeds are small, round, and have a dark outer cover which helps preserve them over the winter months. Offsets can be taken in several ways depending on how you want to propagate your spiderwort plants. One way, if it’s a small plant, is to gently separate an offset from the parent and then pot it up.

Another way, if you have larger spiderwort with multiple offsets around, its base can be done by digging up a portion of the mother clump and separating out all of the little plants that are attached at their bases. It’s best not to disturb them in the winter months because the roots are shallow and freeze easily.

Sempervivum arachnoideum care

Sempervivum arachnoideum

Sempervivum arachnoideum is easy to care for as long as it has plenty of drainages (like gravel at the bottom of a pot). It requires very little water throughout the year except during its growing season. It requires very little fertilizer throughout the year, although it will benefit from a yearly application of compost when not flowering.

Light requirements

Sempervivum arachnoideum grows in full sun, so it is best to place the plant in a location that receives at least six hours of sunlight per day. However, this succulent also does well under shade and semi-shade conditions. As long as your spiderwort has enough light overall during the course of the day, it will be fine.

Soil/potting mix

As with most succulents, Sempervivum arachnoideum requires soil that drains well and is not too high in nutrients. Choose a potting mix that consists of sand, peat moss, and perlite to ensure the plant has great drainage and aeration. You can also use coarse river sand or grit instead of regular potting soil.


Sempervivum arachnoideum is not a heavy feeder, so you don’t need to provide it with fertilizer every two weeks during the growing season. You can use an all-purpose or cacti and succulent plant fertilizer once in late winter before new growth begins.


As with most succulents, Sempervivum arachnoideum requires very little water and can actually be killed by too much moisture. Water the plant when its soil is dry to touch in spring and summer; reduce watering slightly during winter dormancy.


This succulent plant is hardy and can tolerate a variety of temperatures, but will flourish best when grown in cool conditions. Sempervivum arachnoideum should be protected from frost as well as heat above 85 degrees Fahrenheit (30 degrees Celsius), so it’s best to keep the pot indoors if you live somewhere with cold winter temperatures.


Sempervivum arachnoideum has some degree of humidity requirements but will do just fine in dry air. If you live somewhere that is extremely humid or where it rains often, misting the plant’s leaves every day to keep them moist can help this succulent look its best.

An ideal humidity range is between 40 and 60%, but this plant will do well in the average humidity of a home. You can also place it on a tray or dish filled with pebbles and water to increase humidity around the spiderwort’s pot; make sure that no standing water is left at the bottom of the dish as you don’t want your succulent to get waterlogged.


Sempervivum arachnoideum spreads via offsets, so you can trim the plant back to almost nothing and it will grow more rosettes. Cut off any dead or dying leaves with pruning shears before new growth begins in spring; this is also a good time for general maintenance on your succulent.

When to repot

If the plant’s roots are growing out of drainage holes, or if you wish to increase its growth rate, repot your spiderwort in spring every two years. Use a well-draining potting mix and leave just one rosette per container; don’t bury the mother plant so only the top leaves remain above soil level.


Sempervivum arachnoideum goes dormant in winter, so the plant will not grow or produce any new offsets during this time. Reduce watering to just a few times per month and place it somewhere cool until spring when you can begin increasing water again.

Sempervivum arachnoideum plants are extremely hardy and will survive many conditions; however, the plant is not indestructible. If your spiderwort has black spots on its leaves or suffers from rot at any point, it will likely die if left untreated, so be careful with watering and repotting schedules to avoid this problem.

Flowers & Fragrance

Sempervivum arachnoideum

Sempervivum arachnoideum produces small, pink flowers that bloom from summer into fall. Although the plant is not as fragrant as its close relative Sedum morganianum (donkey’s tail), it has a pleasant scent when its leaves are touched or brushed against.

Growth rate

Sempervivum arachnoideum plants are slow-growing, but also very long-lived. If you take great care of your plant and give it the right conditions to thrive in when young, there’s no reason why you can’t enjoy its company for decades or more!


Succulents such as Sempervivum arachnoideum are non-toxic to people, pets, and wildlife. Although the leaves of Sempervivum arachnoideum are poisonous if ingested, and skin irritation is possible with any contact. Keep the plant away from children and pets to avoid accidental poisoning or injury; use gloves when handling these succulent rosettes as well.

They’re an excellent choice for container gardens where they can be enjoyed from a distance as well as up close!

USDA Hardiness Zones

Sempervivum arachnoideum is hardy down to zone 4, and occasionally as low as zone 3.

Sempervivum arachnoideum plants are extremely adaptable and will do well in a range of conditions depending on where they’re planted! They can survive winters with heavy snowfall or frosts and hot summers, so they’re a versatile choice for container gardens and outdoor beds.

Pests and diseases

Spiderwort is relatively free of pests and diseases but can be infested with mealybugs or aphids. Treat any problems you notice as quickly as possible to prevent them from spreading throughout your plant; if allowed to linger, these insects will cause deformities and black spots on leaves before killing the succulent altogether.


Sempervivum arachnoideum is a wonderful little plant that offers tons of variety, so you never have to worry about being bored with your succulent collection! Whether planted in containers or beds outdoors, this hardy species will do well as long as it has the correct exposure and care.

If you have enough light and space for this little plant, there’s no reason not to enjoy its company indoors or out over many years. It is extremely hardy and low maintenance with a pleasant scent!

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