Crown Of Thorns Plant Propagation – How To Propagate Crown Of Thorns
By: Bonnie L. Grant, Certified Urban Agriculturist
Euphorbia, or spurge, is a large family of plants. crown of thorns is one of the better known of these, and a standout specimen. Crown of thorns plant propagation is generally through cuttings, which is a fast method of establishing the plant. Do crown of thorns have seeds? They can produce seed if they bloom, but germination is fickle and it is much easier to establish plants from cuttings. Below is a guide on how to propagate crown of thorns in your home.
Taking Crown of Thorn Cuttings
Crown of thorns is native to Madagascar and was introduced to the United States as a novel houseplant. As long as they get a period of dry and a period of wet, these plants can flower all year around. Their stems and leaves contain a latex sap that some growers might be sensitive to, so it is a good idea to wear gloves when taking crown of thorn cuttings. The best time for cuttings is spring and summer when the plant is actively growing.
Use a very sharp knife or razor blade that is clean to prevent excess damage and disease passage to the parent plant. Cut straight across the tip of a leaf, taking a cutting 3 to 4 inches (7.5 cm.) long. Spray cold water on the parent’s cut end to prevent latex sap from leaking.
The next step is important to propagating crown of thorns through cuttings. Lay the cuttings on newspaper in a cool, dry place and allow the cut end to callus. This promotes cells that can turn into roots and helps prevent rot when you insert the cutting into soil. It usually takes a couple of days and the end will appear puckered and grayish white.
How to Propagate Crown of Thorns Cuttings
Propagating crown of thorns with cuttings is much easier than seed. Seed can take months to germinate and may not do so at all if conditions aren’t just perfect. Cuttings need a good medium of equal parts peat and sand that has been previously moistened. Set several cuttings in to a 4 to 5 inch (10-12.5 cm.) pot for a quicker, fuller effect.
Insert the callused end into the medium and bury so the cutting is just standing up. Keep the medium lightly moist, but avoid too much water and do not use a saucer or allow standing water. Rooting can take 12 to 14 weeks, but plants often flower shortly after that period.
Crown of Thorns Plant Propagation from Seed
Do crown of thorns have seed? Well, of course, they do, but Euphorbia seeds are only viable a short time and must be sown immediately. You can encourage your plant to produce seed by pollinating it by hand. Use a fine paintbrush and transfer pollen from one flower to another.
Once you see the developed fruiting capsule, allow it to ripen and then remove it and split it open over a piece of paper to collect seed. Use the same medium in which you would to root cuttings, but in flats.
Sow the seed on the surface of the soil and cover lightly with sand. Keep the flat lightly moist with a clear lid or plastic over it and place on a heated pad in bright light.
Once you see baby plants, remove the lid and mist the soil to keep just the surface wet. Transplant babies when you see a pair of true leaves.
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Crown of Thorns Plant – Care, Growing, Watering, Flowering, Propagation
The Crown of Thorns plant, Euphorbia milii, is a blooming succulent that grows into a woody shrub that features sharp thorns on its stems.
The plant’s name has biblical connotations — it’s believed that the crown of thorns worn by Jesus Christ as his crucifixion was made with the stems of this plant.
Because of this, the plant is also known as Christ Plant or Christ Thorn.
If you’re not put off by this story and you want to grow the Crown of Thorns plant indoors, follow my tips below.
Euphorbia Milii Features: An Overview
- Euphorbia Milii, also known as Crown of Thorns, is a broad-leaf evergreen, native to Madagascar.
- It has fleshy, bright-green leaves, thick sharp black thorns, and tiny flowers that grow in clusters and that are subtended by spectacular red or yellow bracts that look like petals.
- In their natural habitat, Crown of Thorns succulents grow 5-6 inches (12-15 cm) in height and they tend to sprawl.
- When grown in outdoor gardens in warm areas like Florida, they grow at 3 inches (7-8 cm) tall, and when grown indoors they are about 2 inches (5-6 cm) tall.
- The sharp thorns of the Euphorbia Milli cover its stems and branches and are 1-2 inches long (2-5 cm) and its leaves are 2-2 ½ inches long (5-6 cm).
- The true flowers of the Euphorbia Milli lack petals and sepals and are small and greenish. However, they are subtended by beautiful petal-like bracts.
- When grown in perfect conditions, the flowers of the Euphorbia Milii will bloom throughout the year, but their blooming season is mainly winter through spring. However, it is quite common for Crown of Thorn succulents grown indoors to bloom from late winter well into fall.
- Succulents and cacti are amazing plants, and hybrids are even better. As a result, plant hybridizers are always looking for new varieties. To know exactly what you’re getting, look for Euphorbias that are in bloom. Local nurseries and shops will probably sell the common varieties of Euphorbia Milii, but you can find a wide range of unique and unusual hybrids online.
Crown of Thorns
As the holiday season approaches, I’m finding that, more than ever before, I’d like to avoid shopping and instead give homemade presents. Lacking any and all skills needed for crafting, I’m looking at ways to give plants, and in particular, plants I can propagate myself. My primary candidate is one you may already have: crown of thorns, which can readily be propagated with stem cuttings, though you must proceed carefully due to its thorns and because the sap can irritate the skin and eyes.
By the way, you may have other candidates for cuttings among your houseplants one that comes to mind is Streptocarpella, which is easy to propagate using stem cuttings read more about it in The Garden Shed, Streptocarpella, Mar. 2020. If you’re a newbie in the plant propagation department, you’ll find expert guidance in another recent article, Creating New Plants from Cuttings, Oct.2020.
Crown of thorns indoors during winter. Photo: Cathy Caldwell
But back to the crown of thorns, Euphorbia milii, also known by other common names, including Christ Thorn and Christ Plant. It seems to have more than one scientific name as well it is sometimes referred to as Euphorbia splendens or Euphorbia milii var. splendens. It is a member of the large Euphorbiaceae (spurge) family, reportedly named for Euphorbus, an ancient Greek physician who is said to have used the sap medicinally be aware, however, that the sticky, white sap is poisonous. Legend has it that the thorny stems were used to make the crown of thorns worn by Jesus at his crucifixion. This plant is a shrub or subshrub, and is a native of Madagascar, where it has a sprawling habit and grows as tall as 5-6 ft. In mild climates, it is grown outdoors and is a common landscape plant in southern Florida. The fact that its sap is toxic may yet turn out to be a good thing research shows it has promise as an anti-snail toxin against the snails that are the intermediate host for the parasite (Schistosoma trematoides) that causes human schistosomiasis, a disease that is prevalent in tropical and subtropical countries.
My original crown of thorns (my Mother Plant) on the deck during summer. Photo: Cathy Caldwell
If you don’t already have a crown of thorns, I highly recommend acquiring one — preferably via a contact-free parking lot purchase. If you’re not familiar with this wonder of a plant, you’re in for a pleasant surprise. Yes, it does have sharp thorns, but few houseplants are as rewarding. For starters, it blooms almost all the time. I have the red-flowered type, and there’s nothing quite as uplifting as its profusion of blooms in mid-winter. And it continues blooming all summer when I move it out on the deck, where it has occasionally attracted hummingbirds. A word of caution about the thorns: be sure to place it where it is out of the way of dogs, children, and other unsuspecting passersby.
Technically, the blooms are bracts that surround the actual flowers, which are tiny and greenish. And if you want to get even more technical, the “blooms” consist of a special structure called a cyathium — which is basically bracts joined together to form a cup. The cup holds a single female flower with 3 styles surrounded by five groups of male flowers, each of which has one anther and five nectar glands. Two of those nectar glands have petal-like appendages — and those are what appear to be the “flower” to most of us.
This is not a plant that’s grown for its foliage. That’s because, as the stems mature, they tend to drop their succulent leaves. But the spiny stems themselves are intriguing, though it is not a cactus. According to some experts, it usually grows to only 2 feet as a houseplant. But give it time, and it may exceed that. My first crown of thorns — which I call my “Mother Plant” — was purchased in the 1990’s and is now three feet tall.
Pruning and Propagating
This plant, which started out as a cutting, has been pruned for a tighter growth habit. Photo: Cathy Caldwell
A crown of thorns can use regular pruning to keep it less leggy and rangy. I didn’t know this in the early years, so my Mother Plant has a wild, disorderly look that might not appeal to all. Nowadays, I do occasional pruning, and I’ve discovered how easy it is to combine that chore with propagating more plants. After my first foray into pruning, I decided to see what would happen if I planted the pruned-off stems. I plopped those stems into a new pot and watered. Voila! I soon had new plants after every pruning. Luck was clearly on my side since this is NOT the textbook way of propagating a crown of thorns. Here’s the correct way to proceed:
“ Remove 3-6″ terminal sections and dip the cut end in cold water or powdered horticultural charcoal to prevent the milky sap from running excessively. Allow the cuttings to dry for 2-3 days before placing in well-drained planting mix (such as sharp sand, perlite and peat) to root. Keep the medium just barely moist – if too dry the cuttings will not root but if too wet they may rot. They should root in 5-8 weeks when temperatures are warm. “
—Crown of Thorns, Euphorbia milii, Univ.Wisconsin Extension
Be sure to wear gloves — and perhaps eye protection – when you’re pruning crown of thorns.
Varieties and Hybrids
A Thai giant hybrid. Photo: cultivar413, CC BY 2.0
There does not appear to be complete agreement on the scientific name for crown of thorns. Euphorbia milii — the species — is typically used, but you will also see it refered to as Euphorbia milii var. splendens, a very common variety of crown of thorns I suspect this may very well be the plant I have. In addition to the red-flowered types, you may have seen the creamy yellow-flowered Euphorbia milii var. Tananarivae, which is sometimes sold as E. milii var. lutea. In any event, the varieties and colors available are extensive, thanks to the work of plant breeders.
The California hybrids are sometimes called the “giant crown of thorns,” — probably due to their larger flowers and stems. These include:
A Thai hybrid is featured in the landscape at Pitzer College in southern California. Photo courtesy of John Rodman Arboretum, Pitzer Campus Plant ID Gallery
The Thai hybrids originated during the 1990’s in Thailand, and many featured larger flowers and a more upright habit than the species. But most of these hybrids have been lost. Today there are only a few growers near Bangkok that export these plants, and they have not been introduced to the nursery trade in either the US or Europe. Nevertheless, the Thai hybrids are popular as collector plants, and are available from specialty nurseries. Among these are:
–‘Jingle Bells’ (pale pink bracts tinged with red and green)
–‘New Year’ (soft yellow bracts that change to red as they age)
— ‘Pink Christmas’ (creamy bracts that develop pale pink and reddish streaks) and
–’Spring Song’ (creamy yellow bracts)
The Thai hybrid pictured at right is quite the eye-catcher. By the way, this photo led me to the John R. Rodman Arboretum at Pitzer College, California I highly recommend taking a look, especially if you’re interested in arid landscaping. John R. Rodman Arboretum/Pitzer College.
The German hybrids tend to have thicker leaves and thinner stems, with flower colors of pink, red, and cream. These include ‘Somona’ (yes, that’s how it’s spelled) and ‘Gabriella’.
The Dwarf hybrids tend to be tolerant of both over- and under-watering and perform well in small containers, includes : Short and Sweet™ and ‘Mini-Bell’.
How to Grow
Crown of thorns is tough and easy-to-grow, so long as it has well-drained soil and plenty of light. It is drought tolerant and has no problem with the dry indoor air of winter. Place it in a south- or west-facing window.
Remember that leaf drop is normal. Here’s a bit of deception that is practiced by some gardeners to encourage retention of leaves on crown of thorns: water it a bit more than strictly necessary and fertilize it occasionally (but not with a formula containing added micro-nutrients because it’s boron-sensitive). If you try this trick, be sure to watch out for root rot, and cut off any brown stems to halt the spread of rot. I haven’t tried this myself if you do, please let me know how it works for you.
The favorable characteristics of this plant make for a long list. And it will be as happy outside in the summer as it is indoors. You may even see hummingbirds checking it out. Now that’s what I call an ideal gift.
Featured Photo: crown of thorns (Euphorbia milii). Photo: Mokkie, CC BY-SA 3.0 via Wikimedia
- Plus One
How to Make a Cutting of a Holly Plant
Many people think of Christmas when they see holly, but the shiny evergreen bush is beautiful all year 'round, and will grow in all but the coldest climates. Deer and birds like to eat holly's tiny red berries, and rabbits often snack on the leaves if left unprotected. Holly is an easy plant to propagate from cuttings, but be sure to plant plenty, so you’ll have enough to spare during the winter holidays. Holly should be propagated in summer to late fall.
Choose a few healthy stems on the upper part of the holly bush and take several cuttings. Make the cuts just below a leaf node--a bump where a new leaf is about to emerge. Cut at a slant with a sharp, clean knife. The stem should be 3 to 4 in. long.
- Many people think of Christmas when they see holly, but the shiny evergreen bush is beautiful all year 'round, and will grow in all but the coldest climates.
- Holly is an easy plant to propagate from cuttings, but be sure to plant plenty, so you’ll have enough to spare during the winter holidays.
Prepare a spot in your garden where the holly will be in full sunshine and dig a hole 12 to 14 in. deep. Add a shovelful of damp peat moss to the bottom of the hole.
Group the cuttings in bundles with the cut ends even, and tie a string around each bundle. Dip the bundles in rooting hormone and plant them in the hole. Replace the soil in the hole. The cuttings should be at least 6 in. below the soil, and completely buried with no part of the cuttings visible.
- Prepare a spot in your garden where the holly will be in full sunshine and dig a hole 12 to 14 in.
Mark the area with a stake so you’ll know where the cuttings are buried. The holly will emerge from the soil next spring.
Common Problems And Questions
Crown of thorns plant not blooming
Why Is My Crown Of Thorns Not Blooming?
Crown of thorns plants need lots of bright, direct sunlight and plenty of water to get the best blooms. Excessive fertilization can also reduce blooming, particularly high nitrogen preparations, as these will promote green growth at the expense of flowers.
Excessive pruning in late summer and excessive temperature fluctuation can also shock the plant and lead to many fewer blooms the following season.
My Crown Of Thorns Plant Is Dying Due To Neglect. How Can I Fix It?
These plants live for decades through thick and thin. Even if it looks barren and forlorn, there’s probably life in it yet. The rule is not to make immediate big changes.
If the top few inches of the soil are dry, give it a thorough drink with conditioned water—but check first. Then continue watering as recommended. Groom dead stems and flowers, but don’t fertilize immediately. Wait until spring and feed very lightly until you see new growth.
Don’t re-pot right away. Wait for the right season, and consider rooting new plants from its cuttings first. That way you’ll be more relaxed about the results.
We Have A Large Crown Of Thorns Plant To Move. Should We Prune Beforehand To Avoid The Thorns?
No, a transplant is better off regrowing roots than dealing with pruning shock. An easier way is to dig it out until it falls over, and handle them by their roots!
Are Crown Of Thorns Plants Drought-Resistant?
Crown of Thorns isn’t a desert plant, but it fares well in dry conditions. They naturally look great when planted beside large rocks or in a pot with other succulent types.
Why Is My Crown Of Thorns Plant Losing Leaves?
It’s natural to lose leaves from the lower part of a stem, but leaf loss all over the plant is usually one of two things:
Overwatering – The plant can handle excess water in the bright light of growing season, but you need to cut back in late fall and winter. If you see (or smell) root rot, remove the damaged portions and rectify the situation.
Changed Conditions – Moving inside can cause leaf-loss, as can a change in light or simply a new location.
Reexamine your watering schedule and make sure their light is sufficient … and give them time. They are forgiving of missteps and can regrow leaves once conditions improve.
Welcome to Smart Garden Guide
Hi, I’m Andrew, and Smart Garden Guide is my website all about indoor gardening and houseplants. I’m here to share my experience and help you have more success and enjoyment growing plants. Enjoy your stay at Smart Garden Guide.