Calandrinia spectabilis, also known as firecracker plant, Calandrinia grandiflora, Cistanthe grandiflora, or rock purslane succulent, is a succulent plant native to Southern Africa and India. It produces green foliage in the spring, followed by bright purple flowers, which are followed by bright yellow berries that can easily be mistaken for true grapes.
Rock purslane can be kept as an indoor potted plant or grown outside in the summer, where it will reach up to two feet in height, as long as it receives adequate sunlight and water.
Calandrinia spectabilis is an herbaceous annual that grows in U.S. Department of Agriculture plant hardiness zones 8b through 11, including the southern and southwestern regions of the United States, coastal sections of California and Florida, the Pacific Northwest, and most other states east of the Rocky Mountains with warmer climates.
This plant has many common names and cultivars, but all plants fall into the same species.
The rock purslane, is one of the most beautiful garden plants in California and thrives in many other states as well as some tropical areas.
Calandrinia spectabilis belongs to the purslane family, Portulacaceae, whose members have succulent stems, typically yellow or purple flowers with five petals, and small edible leaves. Purslane has become popular in recent years due to its nutritional value and ease of cultivation.
Origin and descriptions
Calandrinia spectabilis is native to Africa and Asia, but it has now spread to parts of America as well. The first sighting in North America was in San Francisco’s Golden Gate Park in 1892. Because of its spreading nature, it has since been classified as an invasive species by California’s Department of Agriculture and Natural Resources.
However, it can also be easily controlled with a well-placed rock garden or border. This small perennial grows about 2 inches tall and produces bright yellow flowers that attract butterflies and bees.
It is also known for attracting birds who eat its seeds. Its leaves are edible as well, but they must be boiled before consumption because they contain oxalic acid which can cause stomach upset if consumed raw.
This plant prefers full sun exposure and light watering once every few days during dry periods. It will grow best in sandy soil that drains quickly.
Calandrinia spectabilis propagation
Calandrinia spectabilis can be propagated by seed, but they are often produced in vitro. Simply place seeds into a 2:1 mixture of vermiculite and perlite. Germination should occur within 10-21 days. Seeds may also be sown directly outdoors after the last frost.
Space this Calandrinia succulent plants apart very well in full sun or partial shade with well-drained soil that is slightly acidic to neutral pH. Plants prefer an average water supply but will tolerate drought conditions once established. Deadhead spent blooms to encourage additional flowering later in summer through fall.
Pinching plants back when they reach 6 inches tall will produce multiple flowers on each stem. For best results, apply a general-purpose fertilizer every 3 weeks from spring until early fall. This annual plant attracts butterflies and bees for pollination.
Calandrinia spectabilis is hardy in zones 8-11. In colder climates, it can be grown as an annual. Rock Purslane’s stems have an attractive reddish-purple coloration that contrasts nicely with other flowers. It can also be used as a ground cover or edging in rock gardens.
How to propagate rock purslane cuttings
When possible, take cuttings early in the morning before plants become stressed by heat.
Whenever you need a piece of Cistanthe grandiflora, simply snap it off or cut it with a pair of pruners. Make the cuttings from 3 to 4 nodes.
Leaving a stump below the node, cut between the nodes (the internode). Cuttings like to root here, so cutting too close to the node makes rooting more difficult.
To form a callus, dip the cuttings in rooting hormone after taking them and let them dry out for a few days.
Plants can be protected from soil-borne diseases by forming calluses.
Fill the propagation mix into the container and pre-water the soil. Pre-wetting makes the mix more stable when the cuttings are inserted because it compacts it.
Prepare your cutting holes with a pencil or chopstick. When you insert the cutting, it prevents tissue damage and removes the rooting hormone when inserted.
To prevent the cuttings from falling over, place them about one-third of the way up in the container.
Rock Purslane plants that are overgrown or old can be replaced with this.
Calandrinia spectabilis care information
Calandrinia spectabilis plants are very low maintenance. You can keep them growing year-round in any well-drained soil, full sun, or partial shade. When watering makes sure to thoroughly soak them and then allow excess water to drain out of the saucer underplant.
They have a longer growing season than some other succulents but they are not invasive. In fact, you will rarely see it spreading unless you want it to because it self-seeds readily. If you do not want more plants, just pull up seedlings when you see them.
The most common pests that attack Calandrinia spectabilis are spider mites, mealybugs, and aphids. For small infestations, just wash off with soap and water if possible or use insecticidal soap, if necessary, for large infestations.
Calandrinia spectabilis does best in areas of filtered light. This means that it should receive no direct sunlight, and if there is a window or door near it, it should be covered with paper to prevent any direct sunlight from getting through.
If you are growing your plant indoors, place it near a window but behind a sheer curtain that blocks out direct sunlight but still allows some indirect light to get through. A south-facing windowsill is perfect for an indoor Rock Purslane plant.
An ideal soil for Calandrinia spectabilis is a well-drained, sandy potting mix that is light and provides good aeration. However, rock purslane will tolerate almost any type of growing medium as long as it drains freely.
As with many succulents, rock purslane can be grown indoors on windowsills or under fluorescent lights. A well-lit area without direct sunlight is best.
Rock Purslane can take more than normal watering, especially in its first year. Letting your soil get completely dry can kill it. Make sure to water every few days and make sure to water deeply. Once established you can let it go longer without watering but keep an eye on it so you don’t let it get too dry.
Allow soil to dry slightly between waterings; overwatering may cause rot. In general, allow the plant’s top 2 inches of soil to dry out before watering again.
If you are growing it in a pot or container, use a pot with drainage holes. This plant does not like wet feet! If you see leaves starting to curl up or yellowing at all, then you should probably give them some water.
If growing outdoors, place under partial shade during hot summer months and when dormant during winter months. If grown indoors place in bright indirect light year-round.
Calandrinia spectabilis prefers a fertilizer rich in potassium, phosphorus, and nitrogen. There are several commercial fertilizers available with a 3-1-2 ratio of N-P-K or 18-6-12. These blends can be diluted with water for use on seedlings and transplants.
When plants are in bloom, it is important to use a fertilizer that has more phosphorus in it, like 5-10-5. Too much nitrogen will result in leggy growth. An alternative to chemical fertilizers is compost tea, which can be purchased from your local nursery or gardener’s supply store.
Compost tea contains beneficial bacteria and fungi that help break down organic matter into nutrients for your plants. To make compost tea, fill a bucket halfway with composted material and top it off with water. Let sit overnight so organisms have time to grow before applying directly to plant roots.
Rock Purslane requires warm temperatures to grow. Ideally, it should be grown in an area that stays between 80 and 90 degrees for optimal growth. It will survive colder temperatures but growth slows significantly.
If you’re not growing your plant in a greenhouse or indoors, be sure to provide some type of heat source. If possible, place your plant near a south-facing window where it can get additional sunlight during the winter months.
Calandrinia spectabilis does best in high humidity. When it is growing, misting it with a spray bottle can increase its humid environment and help keep it looking lush.
If you have a drip watering system in your house, you can also put one of those close to your plant. It will pick up moisture from there and slowly water your plant throughout the day or night. Just be sure to not overwater it when you do that!
The ideal humidity range is around 70 to 80%. If you don’t have a way to measure that, try sticking your hand over it. If it feels hot and humid, you’re good. If not, misting can help.
Rock purslane pruning
Cut back any flowering stems that have finished blooming on your Calandrinia spectabilis to encourage lateral growth. Use a pair of pruning shears, and make each cut just above a node. You will want to remove all flowers to encourage more lateral growth and keep your plant from becoming too leggy, which could result in a flop.
Make sure you are using pruning shears and not hedge clippers, which can damage your plants’ fibrous roots. Many gardeners use clippers on succulents but need to be very careful!
When to repot
Calandrinia spectabilis is a warm-weather grower and should be transplanted in spring when new growth begins to appear. Plants can be potted up into a larger container using soil that is well-draining, such as a mix of two parts river sand and one-part potting soil.
Repot plants only when they become root-bound in their existing containers. Water thoroughly after repotting.
Calandrinia Spectabilis needs to be overwintered in a cool, dry location or outdoors. If kept indoors, it is important that it does not get too cold or wet. They will die if temperatures drop below 32 degrees Fahrenheit.
The plant should be allowed to go completely dormant, meaning no water and no light until springtime when temperatures are warmer and more consistent.
Keep your plants in a place where they can get some sunlight but not direct sunlight. Temperatures should stay between 50-65 degrees Fahrenheit. Water sparingly during dormancy. Do not let your pots dry out completely but do not keep them soggy either!
You may want to consider repotting Calandrinia spectabilis into slightly larger pots before you put them away for winter so they have room to grow once they come back out of dormancy.
Rock purslane flowers & fragrance
Rock Purslane is an impressive, bright-colored annual flower that does very well in container gardens. Its unique and showy white blooms will fill your garden with color in a short amount of time. Calandrinia spectabilis is very easy to grow and maintain and makes for a great ground cover plant or even just as a border along walkways.
Calandrinia spectabilis is succulent and grows very quickly in warm weather. New plants can be started from seed or from clippings of stems that appear in late spring or early summer.
For propagation purposes, you should take at least two inches of stem and place it into some moist sand or soil. Keep it outside and in a warm environment until you see new growth appear. Don’t expect results for about four to six weeks!
Calandrinia spectabilis contains cyclopropenoid fatty acids and saponins, which inhibit plant cell division. When ingested by animals, these compounds can cause severe vomiting and diarrhea. In humans, ingestion of one leaf has been reported to cause gastric irritation and purging.
Not much is known about Calandrinia’s toxicity in cats or dogs. However, it is highly recommended to keep animals away from any part of Rock Purslane as ingestion may result in severe gastrointestinal upset or worse.
USDA Hardiness Zones
Calandrinia spectabilis will thrive in USDA hardiness zones 10 and 11. In zone 10, it can be grown outdoors year-round, while those in zone 11 can grow it outside during warmer months. In colder areas, it should be grown indoors or as a houseplant. This plant is sensitive to frost and should not be exposed to temperatures below 50 degrees Fahrenheit.
Pests and diseases
The most commonly seen pests and diseases for Calandrinia spectabilis are spider mites, aphids, whiteflies, caterpillars, and leaf miners. There are many available insecticides in your local nursery that will control these insects. If you choose to use an insecticide, make sure it is labeled for use on rock purslane.
Rock Purslane, Calandrinia spectabilis, is one of the most popular succulents. It is a great beginner plant and an excellent choice for children who are interested in learning about plants.
We highly recommend it! However, you must keep in mind that like all succulents, rock purslane needs to be watered sparingly. If overwatered, they will rot quickly and die! So please take good care of your new friend by giving them plenty of sunlight and water only when they need it. Happy growing!