It seems like succulents have become very popular over the last couple of years. I believe this is because succulents are colorful and exotic-looking. One of the largest genera of succulents is Crassula.
Crassula is a genus of succulent plants that contains over 200 species. The most well-known plant in this genus is the Jade Plant (Crassula ovata). However, many plants in this genus consist of a tower of stacked triangular leaves. Many species have tiny flowers that grow during the fall and winter.
Although many of us think of Crassula plants as houseplants, they will grow as shrubs in warmer climates. I have even seen Crassula ovata bushes in Southern California.
About Crassula
The name Crassula is derived from the Latin name “crassus” which means thick. This refers to the plump leaves that are characteristic of some plants in the Crassula genus. Carl Peter Thunberg (1743-1828) first describes this genus after his trip to the Mascarene Islands in 1780.
The genus Crassula grows in parts of Europe, North America, South America, and New Zealand. However, the largest species-level diversity can be found in Southern Africa (Jürgens, 1995).
Many plants in this genus grow as a tower of stacked triangular leaves. However, these towers will “spread out” over time as the plant grows larger. My Crassula capitella var thyrsiflora (Pagoda Village) maintains the stacked triangular look until the stems grow longer than 10 inches. Then the leaves spread out on the stem.
Most species within the Crassula genus will form tiny, tubular, cigar-shaped flowers during the fall and winter. Although, I have seen flowers growing on my Crassula all year. These tiny flowers are described as unremarkable by many botanists. However, I think they are very beautiful and delicate looking.
The majority of the plants belonging to the Crassula genus are polycarpic meaning that they flower and set seeds multiple times before dying. There are some species that are monocarpic meaning they flower once in their life.
Another unique aspect of Crassulas is that they will prune themselves (at least to a degree). Random leaves will fall off, and new plants will grow from these fallen leaves.
Crassula plants will thrive in USDA Hardiness Zone 9 or 10. They can tolerate brief spurts of cold weather and a little frost.
Best Soil Mix For Crassulas
The most important aspect of soil is that it drains rapidly. Because Crassula plants are native to southern Africa, they are adapted to coarse soils with low fertility.
Crassula plants can grow in acidic or slightly basic soils. However, like most plants, they can suffer from nutrient deficiencies in soils with extremely low or high pH.
Potting soil mixes made specifically for succulents or cacti are generally appropriate for succulents in the Crassula genus.
If you would like to mix your own soil, combine the following components.
- 1 part peat moss
- 1 part organic matter
- 3 parts sand
Watering Crassulas
Like other succulents, it is important to not keep the soil moist all the time. This could result in an anaerobic environment where harmful pathogens and fungi can thrive. These harmful organisms cause root rot.
There are some species of Crassula that prefer to live in waterlogged environments. These species include:
- Crassula natans (Floating Pigmyweed) – an aquatic annual succulent that has branches that grow up to four inches long.
- Crassula peploides – a low-growing succulent plant that forms a mat when the leaves spread.
- Crassula vaillantii (Narrow-leaved Mossy Stonecrop) – a plant with long stems and pink petals. They flower between February and April, and they grow well in exposed rocky areas.
Before watering your Crassula, stick your figures in the soil. If you feel any moisture in the top few inches of soil, hold off on watering. Let the soil completely dry out. Then water the plant thoroughly. Make sure any excess water can drain from the pot.
Signs of under watering include leaf spotting/discoloration and leaf drop. Similarly, signs of overwatering are brown stems and leaves, mushy roots, mushy stems.
Light Requirements For Crassulas
Crassula succulent plants like a lot of light. Some species like the Jade Plant are more tolerant of shade. However, if you place a Jade plant in the shade, their leaves will be a bit larger, and the spacing between the leaves will be longer. This results in a “leggy” appearance.
If you want your plant to have a shorter and stickier appearance, make sure you put it in an area that gets a lot of sunlight.
It is also important to note that the amount of sunlight also impacts the color of your plant. More sun exposure will cause your succulents to turn a more vibrant color like red or orange.
During the warmest parts of summer, I do recommend that you place your Crassula plants in partial shade. This will minimize the chance of the flowers burning. I have left my Crassula pagoda in full sun during the summer (in Southern California), and the little white flowers burned to a crisp within one day.
Growing Crassulas Indoors
Most Crassula species can be grown indoors if they are exposed to enough light. These plants should be placed in a southern or western facing window that receives at least six hours of direct light each day.
Alternatively, you could use grow lights to keep your Crassula succulents happy and healthy. This is particularly a good idea during the winter when the days get shorter.
You can purchase these grow lights on Amazon for under $20. If you want to buy another grow light, just make sure you purchase daylight bulbs with a color temperature between 6000 and 6500 Kelvin.
Place your grow lights between 6-12 inches from the plant unless the light throws off a noticeable amount of heat. In that case, place the grow lights 1-4 feet from the plants.
Do not keep the grow lights on all day. Succulents need darkness each day in order to stay healthy. I recommend keeping your lights on about 12 hours each day.
Ideal Temperature Range For Crassulas
These types of succulents prefer cooler summer temperatures (65-75 degrees Fahrenheit). However, my Crassula plants seem to do okay even when the temperature exceeds 85 degrees Fahrenheit. Eventually, Crassulas will go dormant and drop their leaves if the temperature gets too high.
While many succulents do not do very well in temperatures below 50 degrees Fahrenheit, Crassula plants can survive lower temperatures. My Crassula plants have continued to thrive despite several nights where temperatures fell below 40 degrees Fahrenheit.
Many Crassula succulents can even withstand brief periods of frost. If you live in an area where the temperature consistently drops below freezing during the winter, it is best to bring the Crassulas indoors.
Fertilizing Crassulas
Crassulas do not have high nutrient requirements and only need to be fertilized occasionally. If your Crassula is planted in a pot with fresh potting soil, you probably do not need to fertilize it at all. However, if your plant has been sitting in the same container for a couple of years, the soil nutrients have probably been depleted.
To add nutrients back to the soil, use a fertilizer made for succulents. These fertilizers should have low NPK grade (Nitrogen-Phosphorus-Potassium), and it should be a slow-release blend. I recommend using an NPK grade of 2-4-2 and 5-5-5. It is best to add fertilizer once or twice during the growing season (spring and summer).
It is important to note that you should never use fertilizer meant for lawn care/grasses. These fertilizers are typically very high in nitrogen and could be harmful to the plant.
Propagating Crassulas
Crassulas are easy to propagate. Simply twist a leaf off of the plant. Then allow the ends of the leaves to callous over. This usually takes a few days. It is important to let the leaves form a callous in order to prevent rot and diseases from entering the leaf.
Then place the leaf in a soil with good drainage. Water the soil when it becomes completely dry. Within a few weeks, you should see a new leaf sprouting out of the old leaf.
Here is a YouTube that demonstrates how to propagate Crassulas.
Repotting Crassulas
Crassulas can stay in the same pot for several years. If you do need to repot your Crassula, it is best to do it during the spring. Make sure the soil is completely dry when you repot. Remove old soil from the roots of the plant and place it into fresh soil. You should keep the soil dry for about one week. Then water lightly for a few weeks while the plant adjusts to its new home. This will prevent root rot.
Pruning Crassulas
When your Crassula plants start to become “leggy,” it is a good idea to prune your succulent in order to maintain that more compact, stacked triangular shape. It is best to prune your Crassula plants during the spring.
