Create free plants using cuttings, including rooting them in water or grafting. Homesteaders and gardeners can never have enough plants but we often have more desire than we do cash. This is your ultimate guide to getting more herbs, perennials, berry bushes and fruit trees from existing plants, be still my heart!
Leslie Halleck is a certified professional horticulturalist. She has spent her 27 year career hybridizing horticulture science with home gardening consumer needs. With her extensive experience, which includes in botanical field research, public gardens, landscape design and maintenance, horticulture and green industry consulting, she is definitely the one to learn from.
Listen to the full podcast, Episode #276 Plant Propagation through Cuttings and Using Rooting Hormones of the Pioneering Today Podcast, where we don’t just inspire you, but give you the clear steps to create the homegrown garden, pantry, kitchen, and life you want for your family and homestead.
What are Rooting Hormones?
Melissa: So today is all about rooting hormones, leaf cuttings, stem cuttings and maybe even grafting. I do a lot of seed starting, direct sowing, and even some cold stratification but I really have no experience when it comes to cuttings, leave cuttings, and even grafting. I would love for you explain the rooting hormones to give us a good base. Then we can talk about the cutting stuff because that's where I want to go next in my gardening horticulture journey.
Leslie: You generally have two groups of people interested in propagation. You have the outdoor gardeners, like yourself, that have experience starting vegetable seeds but haven't messed around with vegetative propagation. Then you have the house plant enthusiasts that have dappled with some vegetative propagation, but have no idea what to do when it comes to seed starting.
So it's really interesting, the varied experiences and the common starting place conundrums when you're used to doing on form of propagation, but you really now want to make that shift and discover a who new way to propagate the plants you love.
Vegetative propagation, or cloning, is when we take a cutting from a plant, a piece of the mother plant, and stimulate it to grow new roots and bud shoots. That's where a lot of people start. They'll start with a pothos ivy cutting in water. That's the classic first foray into vegetative propagation for a lot of people. Luckily plants like that, that produce aerial roots, are super easy to root. But a lot of plants that you take cutting off of can be a little stubborn and slow to root.
Say your taking a tip cutting off a citrus plant. That's just a little woodier. That's not a fleshy tropical and can take a long time to root. Oftentimes those cuttings will rot before you ever get them to root, which is really what vegetative propagation is all about. And same with seeds. It's a race to root before you rot. That's what I always like to say.
It's a race to root before you rot.Leslie Halleck
The faster you can stimulate that cutting or seed to germinate or grow new roots, the more successful it's going to be, and to help with speeding up the rooting process and make cuttings more successful, I will often recommend rooting hormones and that's the place of confusion for a lot of beginners. You know, what are these rooting hormones?
How Does it Work?
Essentially, it's a pretty simple process. What you're doing is using a product that simulates a natural hormone in the plant to stimulate and speed up the rooting. Plants have hormones like we have hormones and there's a group of hormones called auxins and they generate the formation of root tissue. And in the plant is IAA or Indole 3 acetic acid, which is the natural hormone that circulates in the plant that does that job of stimulating new root tissue.
You can buy root hormones that are a synthetic product that simulates that, and they're called IBA or indole butyric acid. A lot of times when you buy a little container of rooting hormone, it'll say IBA on it. Essentially it's just a synthetically formulated replication of that natural plant hormone. You dip your cutting in it, or you add it to the water that you're rooting in and it helps that cutting create new root tissue much more quickly than it would if you didn't use it to put it very simply.
There are a few different types of rooting hormones. You can get it in a powder, gel or liquid form. One thing I really recommend with rooting hormones is that you don't dip your cutting into the container that the rooting hormone came in because you'll end up introducing organic matter in there and that can cause problems. Pour a little bit out into a bowl, dip the end of your cutting in it and then put that cutting into whatever substrate you're using.
Natural Rooting Aids
Melissa: You said synthetic hormones and since I'm very natural minded are there any natural hormones that can be used?
Leslie: There are a few natural ways that you can go if you don't want to purchase the synthetically manufactured plant hormone which will be called rooting hormone. You can use rooting stimulants, which aren't the same thing. They're not going to be a rooting hormone, but they're natural products that can aid the cutting in being able to root more successfully.
Liquid seaweed is one that I like to use and you've probably used it in many other ways in your garden. What that can do is creates a conducive environment in the substrate that makes it easier for that cutting to root.
Honey will do the same thing. It's essentially an antiseptic and antifungal. A lot of times it's the fungal growth that causes the cutting to rot before it roots. So you can dip your cutting in some honey to help cut down on pathogens. It's not necessarily directly stimulating root growth, but it's creating better conditions for that cutting to root before it rots.
Willow extract, which you may or may not be familiar with, is actually a natural root simulator because it naturally contains those auxins that are in the plant. So you can use that as a natural homemade rooting hormone. Willow extract might be something you'd want to look into if you're really looking for something that will directly help root development. If you're looking for a natural product to create better rooting conditions then liquid seaweed and honey are your two options in that department.
Melissa: Would it be beneficial to use both together? Like the honey and willow extract together? Or should you choose just one or the other?
Leslie: Probably just one or the other because if you're using a rooting hormone you need it to come in direct contact with that tissue that's going to generate new roots. I think it could get mucked up if you're trying to use honey with a root stimulator. I'm not sure how effective that would be.
You can always experiment with them separately. As a botanist and a horticulturist, experimentation is always fun. You could do something as simple as a pothos ivy. Take a bunch of cuttings off and try these items and see which one works best for you.
It's also going to depend on if you're using a medium to start cuttings that has any organic matter in it. That's where using an antiseptic or liquid seaweed is probably better. It's that organic matter that's going to breed microbes and fungal issues more quickly. If you're using an inert media or even just water I suggest using a rooting hormone because there's no microbes for you to be feeding with that liquid seaweed.
Best Practices for Stem Cuttings
Melissa: Knowing that a lot of my listeners focus on food production, what are some things that we need to be looking for when selecting plants for cuttings? What are some best practices? Walk us through this from the very basic beginning.
Leslie: A clean healthy mother plant, that's what we call a plant you're going to take cuttings off of. If you have an oregano or basil in the garden and you want to propagate more of those herbs your best chance of getting really great healthy new cuttings is to start with a mother plant that doesn't have any problems. A plant that is nice and sturdy and healthy and doesn't have any pests or disease or fungal issues specifically. If there's any leaf spot or anything like that going on it's going to carry over to your cutting. So you always want to make sure that you're starting with a mother plant that is clean and healthy.
It's also better to take cuttings, if you can, earlier in the day when the plants are very turgid. If it's hot and they're a little bit heat stressed, or it's dry, probably not a good time of day to take cuttings. So healthy, clean plant, no pests or diseases.
You need a plant that's big enough that if you take some cuttings off, you're not going to decimate the plant that you have left. I always try to take a few cuttings from a few different plants just so that I'm not completely taking that mother plant back down to the two little nubs.
It just really helps to start with a clean healthy mother plant. Sometimes I'll get a question about whether it's ok to take a cutting from a plant that's tanking, thinking that possibly they can save that plant. Well, only if you some clean healthy growth. If it's in decline because it's got some sort of systemic issue or a fungal or bacterial infection, then the last thing you want to do is take cuttings off of it. Put it into the compost pile. Cut your losses on that altogether. That's my best advice when you start taking cuttings. Just make sure you're taking cuttings off of a plant that's worth taking cuttings from.
Melissa: When you are taking a cutting, do you need a certain amount of leaf sets on the piece that your cutting?
Types of Plant Cuttings
Leslie: Basil is a great example. When we start getting into the types of cuttings, the most common type you're going to take is called a tip stem cutting. So if you look at that basil plant, which is in the mint family, it has nice big stems and nodes where those leaves meet the stem and it's pretty easy to see. It's pretty quick to root.
For those new to propagating I always recommend learning to take cuttings from basil because it's one of the easiest ones for you to try. That very tip of the growth on the top of that stem where the two leaves are coming out, basically if you go back two to three nodes (where the leaves meat the stem), you can cake your cutting which has two to three nodes on it, remove the bottom couple sets of leaves, and that's going to be an adequate stem tip cutting.
Now, once you've chopped off the head of that stem (taken the tip) what you're left with are called leaf bug cuttings. You can keep going down that stem and take additional cuttings that have the nodes on them where new buds can grow and emerge. And you can root subsequent leaf bud cuttings off of that main stem. This is called a leaf bud cutting.
Once you've removed the tip growth you then have those lower nodes where there are leaf buds that kind of merge. So the difference is that tip cutting you get is going to have that mirror stem at the top. It's going to look really nice and pretty and round on top, just the the plant that you have. Once you go down to the leaf bud cuttings you're going to have that cut central stem and you're going to get two new main bud shoots that come off the side of it. So it's going to take a little longer for a leaf bud cutting to fill out on the top as new plant.
The tip stem cuttings are the easiest way to get the fastest, nice full grown plant that you want. Then the leaf bud cuttings, as you go down the stem, are going to take a little bit longer, but you can get multiple cuttings off of one stem by taking a stem tip cutting and then several leaf bud cuttings below it.
Melissa: I assume it'll root pretty fast and begin growing. So the advantage is to take this leaf cutting in order to get more basil with our example here. I assume you're getting a jumpstart by doing this to actually getting more leaves and harvest faster than if you're just growing it from seed. Is that a correct assumption?
Leslie: Absolutely. Cuttings, especially with a fast rooting plant, such as basil or oregano – really aggressive growers, if you're looking to build up stock in your garden or give away plants they are great for that. You're going to get a transplant that can go out into the garden or into a pot much faster, depending on the crop, a couple months faster. It can take quite awhile to get a tomato from seed to transplant to go out in the garden, depending on your climate. That's an eight to 10 week process to transplant for me here in Texas. I could take a cutting off a tomato plant and have a transplant ready to go in about a month that can go out in the garden. That's pretty cool.
So you can speed up your transplant production, and it's also the only way to go, vegetative cloning, if there's a particular variety that you want. We know that hybrid varieties don't grow true from seed. If you have a hybrid tomato the only way for you to get that plant again, and the way that it's propagated commercially, is by stem cuttings. It definitely speeds everything up. It also ensure that you're going to get a clone of the same exact mother plant instead of a seed variant.
Melissa: I do a lot of seed saving and pretty much predominantly only grow open pollinated heirlooms.
Leslie: But you can do the same. If you have a nice green zebra and want to take some cuttings from that and wanted to take some cuttings of that and make more plants much more quickly, instead of waiting for seeds, you can do the same thing.
Melissa: So, I need more lavender on my homestead. Even with doing seed stratification and trying to start lavender from seed, it's kind of a bugger. Walk me through taking a cutting of lavender to grow more plants.
Need to Know
Leslie: First I have to be, because I'm in the horticulture industry, I have to give you the disclosure that a patented hybrid is legally not allowable for you to propagate. A lot of people don't realize it's like intellectual property. It's like a photograph from an artist or a song from a musician. If someone has bred a hybrid lavender and that lavender is patented, then legally you may not propagate it. Especially if you have any intention of selling plants. That's a big no no. So first thing to do is make sure that what your purposes are not going to be propagating a patented lavender or any other type of patented plant for that matter for distribution. Most of the time, if you're just doing it for yourself, no one's gonna show up at your doorstep. There's many patents on lavender. So I just have to put that out there for everyone's edification.
Lavender is a little bit of a bugger for a lot of reasons. It's just slow. And if you think about it, a lot of plants that are very drought tolerant may be used to growing in climates where rainfall is intermittent, so a slower growth habit is adventitious. But it also means things are slower to root, slower to sow. And lavender is a bit woody and so once you get into that woodier tissue, it's going to take longer to root. I recommend that if you're going to take cuttings take tip stem cuttings, only go back a few inches from the tip of the growth. You want a stem that is medium density, not necessarily super, super soft at the tip of the growth stem, but not back to where it's gotten really woody.
You want that in-between texture to the stem, and again, you're going to want several nodes. Two to three nodes is good. You don't want a cutting that's too large because with no root system on it, it can't really support itself. So all that extra foliage and all that growth, it may not root fast enough for you.
Lavender I usually recommend using some type of rooting hormone. So for that you may try the willow extract because the faster you can get it to root the better. I also don't like to root that in organic matter. I would definitely recommend something inert, meaning something like rockwool, coir, or perlite where there's no organic matter there. You can also use automated aeroponic propagators.
If you have my book, Plant Parenting, I explain all of these things that I'm going through in the book. I show you want an automatic propagator is. I use little automatic propagators for cuttings of woodier plants that tend to be trickier to root that tend to rot before they root, such as citrus and lavender. What you do is suspend a cutting in this little reservoir and it circulates water all the time around the end of the cutting. It's basically like water rooting, but with aeration, which is important. And I use a rooting hormone.
Lavender also doesn't like cold wet soil. That rots it as well. Clean, rooting hormone, a tip stem cutting with two to three nodes and remove a bunch of the leaves (don't leave a bunch of leaves on there cause they'll just decay) and use an inert growing medium. I like to use rockwool if you're going to use a substrate.
Melissa: So stay out of the soil and the potting soil.
Leslie: Potting mix tends to be inert. It doesn't actually have organic matter. Potting soil means it has some form of organic matter in it, like composted humus or worm castings or composted manure. Those are going to be trickier for you to do root cuttings in for anyting not inordinately fast because there's a bigger chance of more moisture, less aeration, and mocrobial growth that can decay that cutting.
Best Time For Taking Cuttings
Melissa: I assume that cuttings should be taken while plants are still in the growth phase. I'm guessing that because it would still have a lot of the hormones circulating throughout. Is there a time of year that you should not try to take cuttings? Or doesn't it not matter?
Leslie: When they're dormant is not a good time to take a cutting. Like you said, when you don't have the active growth you don't have the active hormones circulating, so it could be very tough for you to root a cutting from something that is dormant, going dormant, if it's gotten cold or you've had that first light frost.
The best time to do it is during that species most active growing season. So spring when a lot of new growth is flushing out, they're prime for that. So that's a great time. Late in summer, depending on where you are. August in Texas is death zone. Everything is stressed, everything is terrible. July and August in Texas I just equate to January and February in Minnesota. It's just the time we don't go outside.
When plants are really dry and stressed it's not a great time either. The best time is dependent upon the species. Generally when you're cutting that nice spring, early summer flush of growth, when plants are actively growing, those are the plants that are going to give you cuttings that are going to root the fastest. So that's a very general rule.
Now, that said, when you get into things like some woody plants, it's actually as easy or easier to sometimes take dormant stem cuttings. Fruit trees and things like that you can do a lot of grafting or cuttings when plants are dormant. It just depends on the species of plant, but for perennials, fresh fleshy annuals, fleshy herbs, when they're actively growing and happy and healthy and very turgid, that's going to be the time to take your best cuttings.
Melissa: Could you talk more about taking a cutting from a plant versus propagating through grafting? Then we can talk about grafting.
Leslie: Taking a cutting off a berry plant, grape vine or fruit tree, it's going to be exactly what I talked about taking basil stem tip cuttings. There's an intermediate step before you get to grafting, which is called layering and air layering. Real-time grafting is a little complicated for a lot of beginners. I like to start off with telling folks how you can do layering first, which is a great lead up to grafting. A lot of plants will make root suckers. You can take stem cuttings off them or you can layer your plant. All you have to do is bend over that cane, bury part of it in the soil right next to where you want it to grow, and it's going to root and grow a new mother plant. You can then cut that away from the main stem, dig it up, and transplant. You can do that with a lot of perennials, berries, and shrubs.
You can take cuttings off of a fruit tree, take a stem that has a few nodes in the tip of the stem, and root it just like you would a basil, but it's going to take a lot longer because it's a woodier cutting than a fleshy annual or perennial. Or you can do what's called grafting. There's been a lot more grafting with fleshy plants like tomatoes in the last few years. Used to be restricted to fruit trees.
How to Graft a Fruit Tree
Grafting is taking a piece of one fruit tree that has desirable fruit that you want to grow and grafting it, cutting a piece of tissue out where a bud would grow in a node on another plant that maybe doesn't produce a great fruit but has a really sturdy rootstock and is tolerant of pest or disease. You're basically inserting the desirable piece into the rootstock piece and fusing them together so that you get the fruit that you want but it has a completely different species of rootstock that is tolerant of the natural growing conditions.
Melissa: I have a plum tree that doesn't have a pollinator for that plum. It's a little self fertile but not great. So if I were to find a plum variety that would be a great cross pollinator for it, I could just take a cutting, pop it on there, and then I don't have to wait for a whole other plum tree to grow to pollinate this one right?
Leslie: Yeah. You'll see all these crazy sort of multi-fruit options out there. They're not all super successful. But yeah, that's a great way to do it. Grafts are going to be successful when you basically meet two pieces of tissue that produce the type of cells that you need to stimulate new root and bud tissue. You basically create a notch in the stem where a bud grows and take the piece of the other fruit tree pollinator that you need, and you notch the base of that stem cutting, slide it in and tape it together. Over time they can grow together and start producing new growth on that graft stem. Now it's got a cross pollinator on the same plant.
Melissa: Am I looking for nodes that are on the trunk or actually on an existing structural branch of the fruit tree to put my graft on.
Leslie: It depends on how old the specimen is that you're grafting onto. On a young fruit tree, tissue on that main trunk may still be somewhat green and actively producing new shoots. And if it is you could graft onto the trunk. If it's an older tree and the main trunk has really gotten very woody and is not producing any new growth anymore, you're better to go higher up into a branch that has greener tissue. It needs to be green actively growing tissue. If it's an old big woody truck, chances are you're not going to have as much success trying to graft there because you're not going to have bud nodes active there anymore. You're going to have to go higher up into the tree to younger fleshier growth.
Best Time to Graft
Melissa: For the fruit trees, dormancy is best? Or you can just do it when it's dormant?
Leslie: When it's dormant, prior to that new rush of spring growth is always a good time to do that. That's just when fruit trees are grafted and planted because of the way their hormones work. You do that graft and then right before spring and then as that plant starts to move into it's spring flush of growth then that union is going to speed up and take. That's just a good time to do that with woody plants, right before that dormancy break and you get that flush of hormones.
When their flowering and fruiting, that's where all their energy is going. It's a little bit different with flower fruiting plants than it is with foliage herbs. Once that fruit tree has moved into reproducing and all the energy is going into flowering and producing seed then the plant is no longer focused on new growth, rather flower fruit production.
How to Know if the Graft Took
Melissa: How do you know when the graft was successful? When should you see new growth from the piece grafted onto the stock?
Leslie: AS long as that cutting that you have placed, as long as it's still turgid and alive it's still good. It'll be a little slower usually because it has to create a new union tissue. You really don't want to see it budding and leafing out too fast, because that means the energy is going there rather than making that joint union. It's going to be a little slower usually. It can take a few months to really do it's thing; just depends on the species, timing, and temperature. That just depends on the fruit tree and how successfully you made that graft union.
It's not going to be instant. You shouldn't expect to see that new cutting that you stuck on that mother plant to take off and start growing at exactly the same rate as the rest of the tree. It's going to be behind in schedule. if it starts to turn black and shrivel up then it didn't work. You'll know it pretty quickly. Usually it's either going to start working and hang in there or it's going to start to shrivel. And that means that it just has not been able to make that vascular connect that it needs to make in order to be a successful graft.
One cool thing that you can try if you're not ready to dive into actual grafting is what we call air layering. This is great to do with citrus. Basically, air layering is you take a stem, scrape away some of the tissue where it's green growth. You damage it essentially. You're telling that plant that it's been damaged and will trick it into thinking it needs to make new roots. You wrap that wound with something like sphagnum moss or coir, then wrap it all in plants or air layering plant propagation rooting balls. You leave it there for a few months and the stem develops a whole new root system. You pop that little ball off or remove the wrap, cut it off the tree and you have a little transplant with the whole root system ready to go. It's really cool.
Melissa: Does that work only on citrus? I am so far up in the Pacific Northwest I can't really grow any citrus here. Does this work on other non-tropical citrus trees or are those just the best candidates?
Leslie: Those are some of the easiest ones, but it will work on a lot of different plants. You can do air layering on lots of different plants. That would be something to try if maybe you've taken tip cuttings off of things that are just not working for you. Anything that is able to develop new root and bud tissue from a node you can pretty much air layer.
Melissa: That might work will with blueberries.
Leslie: With blueberries, you could do some ground layering as well. If you think about it, air layering is the same thing as ground layering, only you're doing it up on the stem. You've just created a barrier around that node or damaged piece of stem for it root.
Melissa: Is there a general rule on the number of grafts onto a tree like a fruit tree?
Leslie: If there are I'm not really sure what they are. I can't say that I'm a fruit tree production expert, I'm sure there are some people out there that might tell you only do 5% of the branches. I think it's more important to look at the overall health of the tree. How many wounds are you willing to inflict on this tree at the same time? It's probably good to do this over a few seasons if you're going to be adding a bunch of grafts versus trying to do a whole bunch all at once.
Essentially you're wounding that tree and every place you create a wound, you're creating an opening for disease and pathogens to move into that tree. The other thing to think about is that you don't want to be doing a lot of grafting on an actively growing tree in early spring whenever fungal diseases or bacterial diseases become prevalent in your area because you're creating those wounds which means more opportunity for that tree to get infected with something.
So that's another consideration. You have to use sterilized tools when you're creating a graft wound. Actual grafting can get a little bit complicated so I usually have people try a few other methods before going into fruit tree grafting.
Melissa: I'm thinking the leaf tip cuttings or air layering are going to make the most sense. I'm kind of excited to play around with this too.
Leslie: Air layering is fun and you can do it with lots of different plants. That's a really fun exercise that you can do if you've struggled with taking the cutting off the plant and then trying to get it to root. You're basically rooting the cutting on the mother plant before you ever take it off.
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