Sempervivum Arachnoideum (The Cobweb Houseleek)

Sempervivum Arachnoideum Featured Image

Sempervivum Arachnoideum is also known as Cobweb Houseleeks. It is a hardy, hairy succulent that grows in clusters and is endemic to the Carpathian Mountains of Southern Europe. Whether you are growing the Sempervivum Arachnoideum in pots, rock gardens, or dry stone walls, the spiderweb-like appearance of the plant will grab visitors’ attention.

sempervivum arachnoideum
Sempervivum Arachnoideum @Pinterest

Not only is the Sempervivum arachnoideum easy to grow, but it is also fast-growing and adaptable to different environments. If you want to grow the Cobweb Houseleeks indoors or outdoors, this article will come in handy.

Description of Sempervivum Arachnoideum

Sempervivum arachnoideum is a creeping succulent that develops green rosettes, which grow up to three inches tall and 12 inches wide. If you nurture the Cobweb Houseleeks very well, they will reward you with pink, star-like flowers and offsets in the summer. After the flowering season, the parent succulent dies, and the offsets replace it.

If you want the Sempervivum arachnoideum to bloom, it is best not to grow it indoors.


As interesting as this succulent may seem, these Sempervivum Arachnoideum succulents get more intriguing. For instance, this plant has many uses besides being a simple, beautiful succulent to own and raise. Sempervivum Arachnoideum leaves have a background of being used as a helpful stopper for nose bleeds. In addition, the juice within the leaves can be used to apply to cuts and as a soother for tooth and ear aches, while the pulp of the leaves can be used as a mask for facial burns and irritated skin.

Sempervivum Arachnoideum Care

For optimal growth, you need to know how to care for Sempervivum arachnoideum with regards to lighting, watering, potting mix, and temperature.

#1. Lighting Requirements

If you want your Sempervivum arachnoideum to be happy always, you need to grow it outdoors. The succulent requires partial to full sun to thrive. If you keep under direct sunlight, do not mistake the purplish-brown color for sunburn discoloration.

If the leaves of the Sempervivum arachnoideum appear to be shriveled and dark brownish, that is a sign that the succulent is suffering from sunburn and needs to be treated to prevent further damage.

You have to acclimate the Sempervivum arachnoideum to full sun if you want to avoid sunburn. Start by exposing the plant to the morning sun for 1-2 hours daily. After about a month, you can introduce the plant to the afternoon sun for about three hours daily.

But bear in mind that a fully acclimated Sempervivum arachnoideum can still get sunburned during a period of intense heat, so you might want to take the plant indoors or use sunshades to protect it, especially when the temperature rises above 100 degrees Fahrenheit.

Place the pot close to an east-facing window if you are growing the Sempervivum arachnoideum indoors. A west or south-facing window could also work, depending on your location.

The biggest mistake you can make is to overwater the Sempervivum arachnoideum while providing insufficient lighting. This could damage the plant beyond repair.

If you notice the stems of the Cobweb Houseleeks are stretching in the direction of sunlight, quickly provide more lighting to prevent the succulent from becoming leggy. This condition, known as etiolation, can result in stunted growth and weak leaf production.

If you live in a poorly lit environment, consider getting a grow light to boost the light intake of the Sempervivum arachnoideum.

#2. Frost Tolerance

One of the great features of the Sempervivum arachnoideum is that it can withstand frostbite and freezing temperatures below 15 degrees Fahrenheit. So, you can leave the Cobweb Houseleeks outdoors throughout the year if you live in the USDA Plant Hardiness Zones 5-8.

You can plant the Sempervivum arachnoideum in the ground if you live in these hardiness zones. It will survive in the rain and cold during the winter.

Nonetheless, if you would like to protect the succulent during harsh weather conditions, consider using a frost cloth or a small greenhouse.

#3. Potting Mix

The soil you grow your Cobweb Houseleeks in determines how well they will be able to resist pests and diseases. Sempervivum arachnoideum grows best in sandy soil with good drainage. Ensure the soil pH is somewhere between very acidic and slightly alkaline (6-8).

Thanks to the long taproots of the Sempervivum arachnoideum, it can get water and nutrients from deep within the soil during drought. This helps it to survive even in rocky, and windy areas. To prevent moisture from evaporating, you can topdress the soil with pebbles.

Using compost specially formulated for alpine plants is very effective for Sempervivum arachnoideum. That said, you can make your potting mix by adding horticultural grit to a shallow pot so the Sempervivum arachnoideum can crawl easily.

#4. Watering Requirements

Watering Sempervivum arachnoideum requires skill and balance. You have to simulate the natural environment of alpines. This means you have to water the succulents at least once a week. It is best to water before sunrise or just after sunset to prevent the evaporation of moisture.

It is also recommended to water during these periods because the water droplets on the leaves might act as a sort of magnifying glass and attract heat to the plant, ergo causing sunburn.

Sempervivum arachnoideum can be renewed after a long period of drought. You just have to water the plant more often and deeply. Watering twice a week for younger succulents can revive them and develop stronger roots.

You do not need to water mature Sempervivum arachnoideum succulents during the winter months when they are dormant. But then, you have to water younger Sempervivum arachnoideum during this period because their roots, which help to tap nutrients from the soil are not yet fully established.

#5. Grooming

Due to being a low-maintenance succulent, Sempervivum Arachnoideum succulents rarely need any grooming, if any, at all. Potential grooming is usually done once the flower-blooming season has concluded, as it is recommended for owners to carefully trim off older flowers to make room for newer ones.

#6. Feeding

These succulents are not too demanding when it comes to feeding schedules. They don’t necessarily need feedings; however, doing so can benefit them and their growth. Suppose you’re choosing to feed your Sempervivum Arachnoideum. In that case, it’s best to use a slowly-releasing fertilizer mixture, preferably a liquid-based one, and apply it once yearly to two years.

#7. Repotting

Sempervivum Arachnoideumr succulents must be repotted once a year, every two or three years. It’s best to do so during the spring or summer when the plant’s growth has slowed. When repotting your succulent, ensure you use the correct soil in the new gardening pot. Fill most of the new pot with the soil. About a third of the way complete is perfect. Next, remove the plant from its current pot and shake or lightly tap it to let any excess soil fall off – this is also an excellent time to do any necessary pruning before repotting the plant. Carefully put the plant in the new pot and cover the root with other soil before watering. Make sure the soil can dry up completely before you water it again.

#8. Pests and Diseases

Sempervivum Arachnoideum doesn’t attract many pests unless they’re poorly taken care of; however, they can occasionally have small cases of aphids or mealybug infestations. As for diseases, the most common diseases for this succulent are rotting of the roots and leaves, weevils, and possible rusting.

Propagating Sempervivum Arachnoideum

The best way to propagate Cobweb Houseleek plants is by removing the offsets and pups from the parent succulents. You must be patient for the Sempervivum arachnoideum to develop pups before you can begin propagation.

To propagate from pups, you have to use only mature pups. As you cut off the desired pup, get some roots. While you can do without the roots, they increase your chance of success since the roots are already developed. Also, stronger pups have higher chances of surviving than tender pups.

To cut the pup, place a sterilized knife between the offset and the parent succulent. Keep the pup in a dry place so it can dry, and the cut can be sealed. Remember, do not expose the pup to direct sunlight so it does not get burned.

An optional step you can take is to put the pup in rooting hormone so that the growth process can be faster. This step is beneficial if the pup is removed without roots.

Once the pup is dry, plant it on a separate potting mix and water it occasionally. Bear in mind that pups require more moisture than mature succulents. So, you have to mist the soil once it is dry. Stop misting when the pups form roots and start watering deeply once or twice a week.

As the new plant matures, you can start increasing its exposure to sunlight daily.


I guess that’s all about Sempervivum Arachnoideum. Whether you plant it indoors or outdoors, this succulent can be healthy and thrive off of neglect – how great is that? This post is only about the introduction. However, I’d love to provide in-depth research on the whole plant.

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Succulent City chief editor


Succulent City

Hey everyone! Welcome to Succulent City! We are all about succulents, cacti, and a bit about air plants. Ten years back, in 2013, we began the journey with succulents. It started as a simple hobby, crafting and selling charming succulent-themed pins and decorations. But as time passed, our fascination with these remarkable plants grew, and we gained extensive knowledge about them. Therefore, Succulent City is the blog as you see it is now. Enjoy your visit and happly planting!

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