Greetings friends, today I want to tell you about an interesting plant – Sempervivum calcareum. I have several varieties of this species in my collection and I assure you that these plants are worth your attention.
Botanical Description
Sempervivum calcareum has a rosette shape. That is, the plant is round but flat. Rosettes can be anywhere from 1.5 to 4 inches in diameter. However, in most cases the rosette is 2 inches across.
The rosette consists of a short but thick stem that transitions into roots. Many leaves grow from the stem. Young leaves appear in the center of the rosette.
The leaves are short, usually less than 1 inch long. They hold a lot of water, which the plant uses in times of drought.
The tips of the leaves are sharp and can range in color from red to dark maroon. A distinctive feature is that often the leaves have a bluish-green color and it is very beautiful.
Sempervivum calcareum prefers to grow in groups. With time a cluster of rosettes is formed in the center of which is usually the oldest plants.
Origin and Habitat
Sempervivum calcareum is native to Europe, namely the Alps. However, it is most often found in the south of these mountains near the sea coast. In terms of countries, Sempervivum calcareum can be found in southern France and northwestern Italy.
Although this species prefers mountains, it does not grow at high altitudes. It is most often found at an altitude of about 1 kilometer above sea level.
This plant prefers rocky areas where there is no competition with larger plants. Often it grows on limestone, which is where the name comes from. This means that Sempervivum calcareum can tolerate alkaline soil.
Despite this relatively small range, Sempervivum calcareum has occupied a great part of the world. I mean that people are actively breeding and propagating this species for cultivation in gardens and collections.
Care and Maintenance
Here I will tell you how I care for Sempervivum calcareum. Over the years I have studied this plant quite well and now I can share with you all the intricacies of this matter.
Light
This plant is a succulent and like all succulents it likes light. It can grow in full sun without any problems. The more sun it gets the more beautiful the color of the leaves will be.
Sempervivum calcareum can tolerate some hours in the shade, but it needs at least 10 hours of direct sun per day. Otherwise the rosette will elongate and will not look beautiful. In other words, full shade is contraindicated.
Soil
I use a poor sandy soil which does not retain any moisture at all. In this way I recreate the habitual conditions for this species.
As I have already mentioned Sempervivum calcareum grows in the mountains on rocky ledges and cliffs and therefore it does not require any nutritious soil at all.
To get the right soil I mix my garden soil with coarse sand and small stones. The result is a mixture similar to that for succulents.
Watering
I never water this species of Sempervivum. The fact is that inside its tissues there is a lot of water reserves and watering can only lead to rosette rot.
Even if I separate young plants from the mother plant and plant them in a new place I do not water them. In this case it is better to make shade over them for 1-2 weeks if the weather is very sunny.
Problems
There are almost no problems with this species as with most others. I have not encountered any serious difficulties during the whole time of cultivation.
However, once or twice the larvae damaged some rosettes from the inside. I solved this problem by cleaning out the damaged part and re-rooting the plants.
It is also worth mentioning here that sometimes the lower leaves of Sempervivum calcareum can rot. This happens in rainy weather if the plant is growing in poorly drained soil.
Feeding
All species of the genus Sempervivum do not need to be fed and neither does this species. The fact is that these plants perfectly synthesize all the substances they need on their own and they get minerals from rocks.
As a result, they are able to grow quickly enough even without the use of fertilizers. Moreover, I would like to warn you against using any fertilizer as it can cause the rosette to become elongated.
Propagation Methods
Propagation of Sempervivum calcareum is quite easy because each year an adult rosette creates several daughter rosettes around it. When the daughter plants are about half an inch across I separate them and plant them in a new location.
The second method of propagation is by seed. All Sempervivum are monocarpic. This means that when the plant reaches 3 or 4 years of age it blooms and dies.
When the rosette is ready to bloom, it stretches into an upright stem up to 8 inches tall. Next, flowers are formed on this stem. After flowering, seed ripening begins and ends when the stem is dry.
If you collect and sow the seeds, you can get a huge number of new plants. Some of them may have unique characteristics and become a candidate for a new variety.
Hardiness
Sempervivum calcareum has excellent frost resistance. It is proven to withstand frosts as low as -30 °F (-34.4 °C).
It is recommended to grow in USDA hardiness zones 4a to 9b. In other words, it can grow almost anywhere in the United States.
Varieties
Because of its interesting appearance, Sempervivum calcareum is very popular among breeders. Until now, they have presented quite a large number of varieties and hybrids to the world. Some of the varieties I want to tell you about in this chapter.
Sempervivum Burgundy Moon
In spring, the ‘Burgundy Moon’ variety stands out with its pink hues, differentiating it from many of the Sempervivum calcareum types. Achieving richer colors requires plenty of sunshine and lean soil. Its growth pace is slow, yielding only a few offshoot rosettes. This variety was developed in Germany in 1998 by Erwin Geiger.
Sempervivum Campagha
Characterized by its vigorous growth, the ‘Campagha’ variety rapidly produces numerous offsets and quickly covers ground, creating a lush mat. The rosettes are notable for their cherry-colored leaves and compact size, giving them a rounded appearance.
Each rosette measures about 2 inches across. Andre Smits in Belgium introduced this variety in 2000.
Sempervivum Dainty Lass
The ‘Dainty Lass’ features leaves in a purple-green shade with red tips. The rosettes, growing to a size of 2-3 inches, expand swiftly. This variety was bred in Belgium by A. Smits.
Sempervivum Extra
The ‘Extra’ variety boasts light green leaves accented with dark red tips, with rosettes growing up to 4 inches in diameter. Howard Willis in Hungary developed this variety.
Sempervivum Griggs Surprise
Known by various names, the ‘Griggs Surprise’ presents a unique, monstrous form. Ronald Byles named this variety in 1958 in the UK, though its exact origins remain a mystery.
This variety produces small rosettes close to the parent plant, exhibiting a slow rate of growth.
Summary
In conclusion, if you decide to have this plant in your garden, you will not regret it. It is very unusual and very beautiful when you look at it closely. You should be prepared to remove weeds around it, but in general it is a very easy plant to grow.
This is the end of my story. I wish you good luck and all the best!