One thing a growing garden needs is plants, and lots of them! To buy enough plants to fill a regular backyard garden can be quite an expensive affair, but, thankfully, it doesn’t have to be that way. Nature provides freely and abundantly, and when we work with nature, it becomes quite effortless, and inexpensive too!
Plants naturally reproduce themselves, and they are more than capable of doing this without any help. We can take advantage of some of the mechanisms by which plants can reproduce themselves to produce an abundance of plants for our gardens.
Many herbaceous plants (plants that do not have a persistent woody stem) and even many woody stemmed plants can be reproduced if a cutting, a short length of the stem or a branch that is cut off, is put into moist ground in a partly shady cool spot. In time this cutting will sprout roots and become a new plant that is an exact genetic clone of the plant the cutting was taken from.
Softwood vs. Hardwood Cuttings
At this point you may be wondering, what the difference is between taking hardwood and softwood cuttings?
- Softwood cuttings are taken during the growing season, where the plants have leaves, so an important consideration is to maintain the humidity levels until roots begin to form to prevent the cuttings drying out.
- Hardwood cuttings are taken in winter, during dormancy, when all leaves have fallen.
When discussing propagating plants by cuttings, the question inevitably comes up – why not grow from seed?
The Difference Between Cuttings and Seed Grown Plants
The difference between growing plants from seed and growing plants from cuttings is genetic variation.
As just mentioned, cuttings are identical genetic clones of the parent plant because this is vegetative or asexual reproduction, as genes only come from one parent.
Seeds can produce plants that are different from the parent plants because seeds are produced by sexual reproduction, they receive genes from a male and female to form. As they are a cross from two sets of genes, many fruit trees are not true to seed, that is, their seeds will produce a different variety of tree from the parent. For the botany purists out there, yes, there are some exceptions, but this is generally the case.
For example, the seeds from a particular variety apple will not grow to be the same variety as the apple tree they came from. The seeds will produce a wide variety of different apple tree types.
So what you may say? Well, consider that not all the varieties of apple would taste good, some may not be palatable or edible at all!
Why do plants do this, mix and match their genetic material and constantly change? Simply, to adapt to different conditions and enhance their chances of survival and reproduction.
Now it should be clear why all commercial fruit tree varieties are grafted, the scion wood that is grafted onto a rootstock all comes from the same original parent plant, or plants grown from it.
The other great thing about propagating using cuttings is that the plant produced has the same genetic maturity as the parent plant. If a plant takes three years to produce fruit when it’s grown from seed, a plant grown from a cutting will be mature if the parent plant is, so a new plant produced from a cutting of a three-year-old plant will potentially fruit in the same year, which saves a lot of waiting around for trees to become productive.
Genetic variation isn’t as big an issue with most herbaceous plants, but we can maintain the variety if it has favourable characteristics, and it’s a great way to produce hardy, mature plants in a hurry.
Now that we’ve covered the basic theory, let’s get down to the practical matters of how to propagate plants from softwood cuttings.
Procedures for Rooting Softwood Stem Cuttings
When propagating softwood cuttings, which have leaves, there are a few extra steps required compared to using leafless dormant hardwood cuttings. Plants transpire (lose moisture) through their leaves, which makes softwood cuttings more susceptible to drying out.
Step 1 – Select Suitable Cutting
- Most herbaceous (softwood) stem cuttings are best taken during the growing season of a plant, from spring to summer, and the best time is early morning, when the plant tissues contain the most water.
- Cuttings are usually about 10-15cm (4-6”) long, from current or past season’s growth.
- Cut below a leaf joint.
If possible, choose strong, healthy, disease-free shoot for a cutting, preferably from the upper part of the plant.
- Avoid taking cuttings from plants that show symptoms of mineral deficiencies.
- Avoid taking cuttings from plants that have been heavily fertilized, especially with nitrogen, as they may not root well.
- Avoid taking cuttings from plants that show moisture stress.
It is important to keep the cuttings cool and moist until they are placed into the propagating medium. When working with cuttings, don’t lay them out exposed to full sunlight, work in a shady spot!
If the cuttings need to be transported, wrap them in a moist paper towel in a plastic bag. If there is a significant delay in potting up the cuttings, they can be stored in a plastic bag in the refrigerator.
Step 2 – Strip Off Lower Leaves
- Remove the leaves from the lower one-third to one-half (1/3 – 1/2) of the cutting to leave a bare stem. This allows the lower portion of cutting to be inserted into the propagating medium, and also reduces the number of leaves from which moisture can be lost.
- Remove any flowers and flower buds when preparing cuttings so the cutting’s energy can be used in producing new roots rather than flowers.
On some plants with small leaves, it’s possible to strip off the leaves easily by holding the top of the cutting firmly with one hand, then using the other hand to pinch the lower part of the cutting and pull gently downwards. If this doesn’t work, trim the leaves away with scissors or secateurs.
If too much moisture is lost, the cutting will dry out. Remember, the cutting doesn’t have any roots yet to pull up more water to replace that which it loses! On large-leafed plants, to reduce the rate of water loss, cut all the leaves in half by trimming the ends off. This also reduces the size of the cuttings, so they take up less space. When new growth with uncut leaves emerges, this is an indicator that the cutting has produced roots and is growing!
Step 3 – Cut Stem Below a Leaf Node
- Cut the stem about 6mm (1/4”) below the lowest leaf node on the cutting.
The leaf nodes are the areas where the leaves grow out from the stem, which are now stubs from where the leaves were removed earlier. If the area of the stem has no leaves, it may still have visible buds from where new leaves will grow.
The reason why we cut near the leaf nodes is because these areas contain a large area of meristem tissue. Meristem cells are undifferentiated cells, similar to human stem cells, that can grow and divide to form various kinds of cells for plant growth, including new roots.
The cells in the meristem divide quickly and form callus to seal the end of the cutting, and then under the influence of the plant’s own hormones, auxin and cytokinin, these callus cells differentiate to become root cells.
Hardwood species that are difficult to root are often ‘wounded’ by scraping away the bark using a knife to expose the light green cambium layer underneath, which helps promote rooting. Herbaceous plants don’t have woody tissue, and don’t have a cambium layer either, and therefore do not require this step.
Step 4 – Dip End of Cutting into Rooting Hormone (optional)
- Dip freshly cut end of softwood cutting into root hormone liquid, powder or gel. Treating cuttings with rooting hormone can increase the chances of stimulating root growth. This is more critical in plants that are more difficult to root.
- If using root hormone powder, be sure to tap the cuttings to remove excess.
Most commercially available rooting hormone products consist of two synthetic auxins (plant hormones), indole-3-butyric acid (IBA) and naphthaleneacetic acid (NAA), discovered in 1935. They have similar functions to the auxin naturally produced by plants, indole-3-acetic acid (IAA) which was first identified in 1934 and are more effective in promoting root formation. Afterwards IBA was also found to be naturally occurring in plants. Commercial rooting hormones usually also contain a fungicide to prevent fungi from causing rotting of the cutting.
It’s possible to make your own natural rooting hormone, see article – How to Make Home Made Plant Rooting Hormone – Willow Water.
Willow water is mild form of root stimulating hormone which contains IBA that can be made quickly and easily from willow tree twigs.
Step 5 – Insert Cuttings into Pot Filled with Propagating Medium
- Fill a pot with propagating medium. Materials commonly used as propagating medium are coarse sand, regular potting mix, coconut coir, or blends such as a mixture of one part peat and one part Perlite (by volume), or one part peat and one part sand (by volume).
- Water the propagating medium to moisten it.
- Insert one-third to one-half of the length of the cutting into the propagating medium. Keep the cuttings vertical and space cuttings far enough apart from each other so they don’t shade each other out so that all their leaves can receive light.
Any medium which will lend physical support, provide moisture and oxygen in the right balance, is low in fertility and is free of pathogens can be used for propagating cuttings. The reason the propagating medium doesn’t need to contain nutrients is because the cuttings don’t have roots to be able to take them up.
The propagating medium also needs to be well-draining to provide sufficient aeration to grow roots. If it is anaerobic (no air), the roots will rot, as very few plants can grow roots in a container of water. Conversely, the medium should also retain enough moisture so that watering is not required too often.
Step 6 – Add Additional Cuttings to Increase Success Rate
Since cuttings don’t always ‘strike’ (grow roots), and some plants are notoriously difficult to propagate, it’s best to add a few extra cuttings into the propagating medium to increase the chances of success.
Even with plants that have really low striking rates, say as low as 20%, if we put in 10 cuttings in, we’ll potentially get 2 cuttings that take root.
Step 7 – Label the Cuttings to Identify Them
I can’t emphasise enough the importance of labelling plants when propagating by seeds or cuttings.
We might remember what plants and varieties we planted on the day, but what are the chances that we’ll remember after many weeks or months that they make take to grow roots? What are the chances of telling them apart?
Step 8 – Cover the Cuttings to Retain Moisture
- Cover cuttings in some way to prevent them drying out while still allowing them to be exposed to light.
- Set the cuttings aside in a bright, warm location, away from direct sunlight.
In order for cuttings to survive, they need to retain moisture within them. The leaves are able to lose moisture via evaporation, but the cuttings unfortunately don’t have any roots to take up more water to replace what is lost from the leaves.
The way to keep the cuttings alive is to maintain the humidity levels (moisture in the air) around them, while at the same time avoiding excessively damp conditions that will cause them to get mouldy and rot!
To do this, we lightly water the cuttings, and then cover thems with some kind of clear plastic that will hold in the moisture, and then place them in indirect light.
- Avoid direct sun, otherwise the cuttings will overheat and cook in their airtight enclosures!
- Keep the propagation medium moist until the cuttings have rooted.
Smaller pots can be placed inside a plastic propagation tray, these sell for a few dollars and last quite a while, they’re available at most nurseries and garden stores. Note the green air vent ‘butterfly’ on the top of the lid. This allows the vents holes in the lid to be opened which lets out the heat if it gets too warm, or to reduce the internal humidity when the cuttings start growing and need more air flow.
Some gardening books recommend covering pots with a plastic bag and securing them around the pot with a rubber band to retain the humidilty. Since the bags collapse around the plant, keeping the leaves wet, the suggested solution is to place a wire loop shaped like an inverted-U over underneath to prop up the plastic bag.
I’ve never been satisfied with that solution, so I came up with a better one. Here’s an effective design for a humidity cover that I’ve devised!
A regular plastic drink bottle can be cut in half, and pushed slightly into the propagating mix in the pots to seal the moist air in. The top halves of the bottles are more useful as the lid can removed for greater ventilation.
Taller cuttings can be accommodated by cutting off the bottom of the plastic bottle only, creating a taller humidity cover. These work like traditional cloches and can be used to protect seedlings in the garden from snails and slugs. Just remember to take the lid off otherwise the plants inside will overheat and get cooked in direct sunlight!
Step 9 – Harden Off Cuttings When They Show New Growth
The time taken for cuttings to ‘strike’ (produce roots) varies, depending on the type of plant, and the environmental conditions – heat, light and season. Some plants root readily while others can take what seems like forever. If the cutting still looks alive, be patient!
Newly rooted cuttings should not be transplanted directly into the garden. They need some time to adapt and harden off.
Hardening Off Procedure for Cuttings
When using the clear plastic bottle cover, the following hardening off process can be used:
- Wait until new growth appear, indicating that the cutting has rooted.
- Remove the lid of the bottle to reduce the humidity level around the plant, and leave this way for one week.
- Next, remove the whole plastic bottle cover, and leave the plant uncovered for a week.
- Move the plant into a slightly sunnier location so it can adapt to brighter light and slightly drier conditions and leave it there for a week.
- Finally, move it out to a location matching its light requirements and necessary exposure/protection.
After hardening off a plant, it can be planted out the garden, or transplanted into a larger pot with proper growing medium (potting mix) to provide it with some nutrients. Avoid the urge to overfeed newly propagated plants, fertilise them lightly, as their roots are still quite delicate.
There’s no hurry to plant out newly propagated plants. Growing them on to a larger size allows them to develop stronger root systems, which makes them much more resilient, and increases their chances of survival when they’re finally transplanted to their permanent location.
That’s one of the topics what I most eager to learn!
Then I can save money from buying new plants.
Thanks again!
cheers.
Charlee
you can propagate most plants from cutting easy but native plants take time also vegimite or honey is good for root hormone replacement
Hi Peter, cuttings vary enormously in how easy they are to propagate, from effortless to downright impossible, depending on the plant! For plants that don’t grow well from cuttings, there are techniques such as layering and air-layering, which I’ll publish articles on soo! I’ve never tried propagating Australian natives from cuttings, the only ones I have in the garden are propagated by seed or by root division. Don’t know much about using vegemite, but honey I do know about. The honey doesn’t actually work as a hormone to encourage roots, but it protects the cutting from rotting – from being attacked by fungi and bacteria, which indirectly assists it in growing roots. Honey is a natural fungicide and antibiotic. In the commercial mixes of plant rooting hormone they use a synthetic chemical fungicide, which is a good reason not to breathe in the fine powder preparations if you’re using them!. Would be interesting to presoak cuttings in willow water, and then dip them in honey, and see if that makes a difference…
I read on another site that cinnamon can also be used on the cuttings to protect from rotting. Does that sound likely?
Yes, dip the cut end in cinnamon to help preventing fungus.
Thank you for the great information. Gardening is A passion I have had for as long as I can remember. Always looking to learn, and try new and old, ideas alike.
Thank you for the information. I was wondering, can mulberry trees root in water too?
In my experience mulberry cuttings need some kind of propagating medium, they will not root in water.
I used to keep silkworms in my classroom, and we would collect lots of little mulberry branches and put them in a bucket of water to keep them fresh. They rooted and I have two trees that came from that accidental propagation. The trees are now a couple of metres high. I think they were white mulberries, but I’m not sure.
Great info! Thanks heaps.
Thanks so much. Just picked up a propagation tray (with lid) at op shop yesterday and wondered what the vents were for. Excited about taking cuttings now.
The vents in the propagating tray are to let air in once the cuttings have taken. When you first put the cuttings in, close the vents so that the humidity stays in the propagator. Once the cuttings have taken root, you can open the vents gradually so the humidity decreases and more air flows, it makes it easier for the cuttings to adjust from a high humidity propagator to the conditions of the outside air. Hope that helps!
I am interested in propagating edgeworthia. I treated it as a hardwood cutting last year and had some success (but I was late in taking the cuttings in the dead of winter). When is the appropriate time to take my cuttings. I live in VA and the edgeworthia is still leafed out.
That’s quite an unknown plant from the same family as Daphne, I’ve seen lots of opinions on how difficult it is to propagate.
If you’re going to try propagating Edgeworthia from cuttings, use semi ripe cuttings in late summer, use rooting hormone.
If propagation using cuttings in unsuccessful, you can try ‘layering’ to propagate the plant. Just bend a low growing branch down and bury the bottom part in the soil, let the top stick up above the ground. You can keep it in place with a piece of wire shaped like an upside-down “U” to pin it in place, you can use weed mat or irrigation pins, or you can place a rock or a brick over it to hold the base below the soil. You might have to wait twelve months or more until roots form.
Another way to propagate Edgeworthia is to dig out any suckers from around the base of the plant with as much roots attached as possible, pot them up and grow them on for a year, then plant them out in the garden.
I have taken several trays of cuttings over the summer and they have lots of new shoots… However they seem not to have any roots. I’m wondering if there is too much moisture in the propagation trays? They are situated in a glass house with a humidity sensor which sprays automattically when the air dries out. How can I tell if the trays are too wet and or what is the reason I cannot see any roots please?
Many types of plant cuttings will put out new shoots before the roots start growing, I’ve experienced that with mulberry cuttings, though these are deciduous hardwood cuttings. Just leave them in there a bit longer in the greenhouse and be patient, the moisture sounds fine if they aren’t rotting away, you’re halfway there, the cuttings will put out roots soon!
Thats a relief. Thanks for the advice. I’ll keep you posted on progress.
Hi Guys, Just wondering what techniques you use to check if there are roots there? I have planted a few cuttings lately and in my efforts to see if there were roots there have taken the cuttings out completely (which I’m guessing is not great 🙂 any tips on how to tell?
Thanks
Wait until new leaves grow, and/or give the cuttings a gentle tug.
Will wisteria and sea-buckthorn root in water. I tried rooting elderberry in a soilless medium and it did not work I put other cuttings in a rooting solution I made from willow cuttings and they started to sprout roots, I potted them up and they did wonderful,
Sea buckthorn can be propagated in several ways, you can use hardwood or softwood cuttings, it can also be propagated by layering and from suckers growing around the plant. Doing some reading I found that some people claim they’ve had success with cuttings in water, it may be worth a try. If anyone has had success please let us know!
Elderberry is very easy to propagate from hardwood cuttings in winter or softwood cuttings in early spring. Great to hear you got them to root in the willow water solution – I have the recipe for anyone who’s interested here.
You can supposedly root wisteria cuttings in water by taking flexible green shoots, treating them with rooting hormone and sitting them in a jar of water for about a month, I’ve never tried it, I’m tempted to give it a go just to see what happens.
i have rooted sea buckthorn in water, they were semi hardwood cuttings taken in august and about 50% of them rooted. they were kept at room temp and if i remember correctly they took about 2 weeks or more to root.
Hi Stephen, I need more specific information, we’re an international website and months are completely meaningless when discussing the critical concept of seasonal timing!
August in the northern hemisphere is the last month of summer whereas in the southern hemisphere it’s the last month of winter! Which season are you referring to?
Trying to propagate currants and wild blueberries in mixed medium (using rooting hormone) under a grow light, spraying with mister once or twice daily; they sprout gorgeous leaves but after a few weeks the leaves dry up and drop off. Do I need to keep them warmer? Cover to keep them more humid? What am I doing wrong?
Great article, thank you! Ive propagated many succulent varieties, but just started vegetable seed collection and propagation. You gave me great concise information, thanks again! Chuck from Forney, Texas
Hello, I just wanted to find out what is the right conditions for hardwood cuttings.Is it humid and warm or humid and cool. If its humid and cool; how is the humidity achieved in the shade? . Currently my greenhouse is covered with a crop cover and stands in the direct sunlight. I’ve got fig,peach, pomegranate, willow, sand cherry, wisteria, bougainvillea, mulberry, passion fruit and some blackberry cuttings. Will all the cuttings strike when subjected to the same conditions or do some plants require different conditions to strike.Thank you.
Humidity is just a function of water vapour in the air, irrespective of heat. A cold, wet, rainy day is extremely humid!
Usually, a bit of warmth helps cuttings strike roots, the whole point is to avoid harsh direct midday and afternoon sun which will just dry out the cuttings and kill them before they have a chance to put out roots.
Peaches are usually grafted to a seedling rootstock, but the rest should be fine. Some, such as willow and blackberry, will strike very easy. They will all put out leaves when spring comes around, and the important thing is to make sure that the cuttings with leaves don’t lose their moisture from dry wind or direct sun, you must maintain the humidity the best you can until they have their own roots.
Thank you. This was very useful.
You’re welcome! 🙂
Do you have a list of HOUSEHOLD Plants that are edible?
Could I eat these?
Aglaonema, (Chinese Evergreen)
African violet (Saintpaulia)
Begonia (cane type only)
Cissus (Grape Ivy)
Chlorophytum comosum (Spider plants)
Coleus
Cordyline terminalis (Ti Plant)
Dieffenbachia (Dumb cane)
Dracaena sanderiana (Lucky Bamboo)
Ficus pumila (Creeping Fig)
Hedera (English Ivy)
Helxine (Babys Tears)
Impatiens
Philodendron oxycardium (Heart Leaf)
Philodendron pandureaform (Fiddle Leaf)
Plectranthus (Swedish Ivy)
Scindapsus (Pothos, Devils Ivy)
Syngonia (Tri-Leaf Wonder)
Tradescantia (Wandering Jew)
Zygocactus (Christmas Cactus)
Please don not try eating your indoor plants!!!
Most indoor plants are subtropical or tropical plants that grow as understorey plants on the forest floor. Most plants that grow in these conditions are highly unpalatable or toxic, that’s how they protect themselves from being eaten! Many contain calcium oxalate in the form of extremely tiny needle shaped crystals.
The plants you list have a better purpose than being edible, they actually purify the air of many toxic volatile chemicals, wee my article here – http://deepgreenpermaculture.com/indoor-plants/
You can actually grow many proper edible herbs and leafy green vegetables in a sunny window indoors.
Most of those plants are poisonous or dangerous for pets, too. We had to put our plants up high for the first few years of our puppy’s life.
These tips are very helpful. I have made cuttings of fig trees for years, but now I am trying cinnamon tree, and it’s proving to be more cantankerous.
This is such a vital information I could not believe when I find it. awesome
Very interesting article, with lots of useful hints and tips, thanks!
I am experimenting and trying to grow silver birches, field maples and red maples from cuttings.
I guess my question looks at things from a slightly different perspective: how do you know whether a cutting is most definitely dead?
For example, the top leaves I left on my birches cuttings are very dry, and some of the maple leaves have fallen since I planted the cuttings (although still looking fresh). Are these signs that the cutting is (almost) gone or it could still survive and shoot some roots?
I think my cuttings are semi-hardwood.
If I can understand when the cuttings are definitely gone, I can replace them and try again.
If you’re growing deciduous trees from cutting you should probably be using hardwood cuttings when they are dormant. You can easily tell when semi-hardwood cuttings are dead, as they change colour and become brittle, like dead branches.
I thought softwood vs hardwood was a choice merely dictated by period of the year in which the cuttings are taken. Brilliant, will try hardwood instead then, thanks a lot for your answer 😀
Hello, How are you?
I would like to please know what I should do when my hardwood cuttings, that I took in winter, begin to flower in spring. This is so because the cuttings I made (wisteria, peach, lilac etc..) had buds on the tips of the previous seasons growth. Now. as spring is arriving these buds are bursting. Should I remove these flowers? Please advise. Thank you. Great post.
Yes it would be a good idea to remove the flowers, as they draw nutrients and moisture from the cuttings.
Great article
Very useful information. .Thank you
What if it is not the right season to plant in dirt after you have rooted in water. Also, can clippings from store bought vegetation be started in dirt such as green onions, lettuce, celery?
If its the wrong season it might not work as well or at all.
Not sure why you would want to regrow annual vegetables to be honest with you, though kids enjoy activities such as regrowing carrots from carrot tops.
Two years ago I found frost resistant two trees of full flower Hibiscus on Staten Island in NY.
They are growing on North service road of SI Expressway after you exit on Bradley Avenue.
I took semi ripe cuttings in end of July and after treating them with root hormone I planted all in pots on shady roof under plastic cover. When I took cuttings I had to remove huge amount of flower buds.
About 50 % cuttings got roots and last year all my plants grow nice to 20″. This year I watched my babies closely and every week I removed plenty buds to allow plants become stronger and run them as small trees. I trimmed side shoots to keep just one trunk which on most of them are almost 36″ tall now. Each plant was tested with single bud allowing to flower and open up to see quality and color. I was so happy to see two plants with white flowers (slightly pinky smudges) and five with dark red. Flowers were bigger than 2 ” in diameter and center filled with extra petals similar to roses. That is my big achievement.
Now I am on hunt for cones and seeds of Cedar Libani, Cedar Atlas (Atlantica) and Cedar Deodara, Italian Stone Pine, Korean Pine and Cedrus Siberica (proper name Pine Siberica).
The last three are commercial producers of edible pine nuts. Korean ones has beautiful bluish/purple cones standing on branches resembling real Cedar.
If you guys see Cedar tree in wipping form as Pendula you will fall in love with them.
The tops of my Chinese elm cuttings are a little droopy. I used rooting hormone and have them in a bag. They look pretty good except for the droop.
This is best reading I found on propagation ….however you dnt speak of orchids propagation
Sorry to disturb you
Dr. Jaffar almahdi
Bahrain
When there are some new leaves and the cuttings are ready to move into a pot, how careful do you need to be with the roots? Obviously the medium they are in initially doesn’t have enough nutrient to keep the plant going for very long, so do you move them to potting mix or something similar as you you would “prick out” a seedling or do you take the initial medium with it and put it all in to the new pot?
I make sure that the cuttings have put on a lot of new growth and have reasonably strong root systems before repotting them. Usually I check to see if the rots are poking out of the drainage holes, or if the pot feels firm from the root system expanding through the medium. I’ve found that if you repot cuttings too early, the root systems can be very small and delicate, making them more vulnerable to shock or physical damage.
Hello, very interesting !
It will be nice to know your opinion, how to propagate the black berry from cuttings.
Hi Pierre, to propagate blackberries, you can take dormant cuttings about 20cm (8″) long in late winter and push them 2/3 into the ground, leaving the top 1/3 with the tip end above the ground. During spring they will put out leaves and roots.
An even easier method which works great when the plant is growing is layering, Take a long cane that touches the ground, and bury the end in the soil, leaving a length of the tip poking out. Secure it into the soil by pinning it down with a U-shaped wire irrigation or weedmat pin, or weigh it down with a rock or brick to hold it in place. When blackberry stems are buried in the soil they will sprout roots. After several weeks you can dig out the rooted branch and cut it from the parent plant.
Thanks a lot Angelo!