I’ve been noticing over the last year that Mind Your Dirt receives a great many inquiries about the Coastal Coral tree. Two of my articles on the species gets read daily, and often several times per day. This article covers the species as a whole, and this article discusses when and how to prune erythrina caffra.
I’ve often wondered what it is about erythrina caffra that causes so many people to make their way to my humble doorstep in search of answers. The species itself is indeed a beautiful specimen tree with an amazing sweeping short and stout umbrella like canopy, both alien and breathtaking bright red flowers and powerful and very organic flowing trunk and branches. Just see for yourself, I went out hunting for photogenic specimens just for you. You’re welcome.
So I can see the interest, but why is so much Interwebish (I know, relax) traffic drawn to this subject? Mind your Dirt offers a plethora of stories of equally amazing species all over it’s back pages. What drives this keen interest to the coastal coral tree?
Then it struck me. Several years ago when I was researching ways to propagate the species online, I had a hell of a time finding solid propagation information. A bit here, a smattering over there; but nothing solid and concise. To quote my past self…
“I scoured The Interwebs for hours looking for cutting propagation techniques. To no avail. Then I stumbled upon a PDF put together by some remote horticultural school in some small farm community somewhere in nowhere USA. The farmers were using coastal coral trees as natural fences and had a technique to quickly propagate large six foot branches! It was absolutely perfect and if I could find it again I’d link it here to give these saviors proper credit.”
Only in this day and age would one consider “scouring for hours” to be any form of extensive research, but if you know how to search effectively it shouldn’t take this long to find info on a relatively well known species. So that’s what I’m here to do; share that seemingly lost information so that it can have a new forever-home on The Interwebs and all you amazing people can begin to grow and love this amazing tree as well! How nice of me huh?
I have tried many different methods for propagation of this species (to grow as bonsai stock). Seeds are perfect, but they take a wee bit longer to achieve a beautiful and stately tree in the yard. I tried taking smaller six inch segments of the new green growth thinking that they would root successfully. I believe I tried about twenty or so of those. All of them rotted into nothingness in short order.
The key is to take larger woody branch sections and allow them to dry out before potting them. Without further adieu, here is how to grow a coastal coral tree…
What You’ll Need:
- Pruning Saw
- Pruning Shears
- Razor Blade (fresh one!)
- Rubbing Alcohol
- A Cool and Dark Place to Store the Cutting (garage or cellar etc.)
- 3-5 Gallon Pot
- Well-Draining Potting Soil (50% organic/50% inorganic)
- rapier-like wit and ninja cunning
1) Selecting a Good Host Tree:
When you find your free-range coastal coral tree, there are a few things to look for. The clone you’ll be making will most likely take on all of the traits as the host plant so if the tree is sickly or disease prone, chances are your clone will be as well. Don’t be dismayed if there aren’t many leaves on the host tree, however, during the spring the coastal coral will drop most of it’s leaves in order to show off it’s amazing flower display. This allows full visibility to all it’s pollinator friends.
You may also want to look for certain traits that best suit your needs like branch and trunk development, although much of this is dependent on how you prune the tree during it’s training. Mostly, look for a tree that speaks to you and draws you in. Once found, make sure to get permission to prune off a decent branch.
There are many state and federal laws in place to dissuade field harvesting in this aggressive manner (and rightly so), so try to find a private property owner that can give you permission or is planning on pruning their tree anyways. That said, ninja cunning is one of the items on the list above, so take that however you wish 😉
You’ll want a branch that will have ample ramification (a subdivision of a complex structure or, in this case, bunches of little branches) as well as a strong trunk. Picture the branch as a tree because that’s what it’s about to become. The more subdivided branching it has now, the less time it will take to grow into a decent full tree. Here’s a good example of what you want regarding ramification (albeit this branch is crazy big for this purpose).
Once you’ve selected your branch, it’s time for surgery!
2) Making the Cut:
Out of respect for the host tree, be sure to make a good clean cut in the proper location so that the wound will heal completely. This is where the rubbing alcohol comes into play! Clean your saw, pruning shears and especially the razor blade before and after using!! This will help avoid any bacterial infections that can cause serious problems to the host as well as the clone.
I chose the following branch because I’m in the process of training and pruning my clone that is now three years old. Initially, this was a five foot long branch.
Not only does it interfere with the overall design of my tree and may cause trouble once the branches get bigger due to over crowding at the fork; but it also stands in the way of another possible future project. This tree will be perfect for a tree house in a few years! Now, I don’t have any children (that I’m aware of) at the moment, but when I was a wee lad (one million years ago) I always wanted to have a tree house. So this is for the future little ones with similar hopes and dreams. The difference being that, unlike my dear poppa bear, I know how to build one.
This branch would interfere with the basic structure of the flooring supports so I wanted to keep a nice open inner structure that has a fairly level branching like this…
I also wanted to get a really nice lateral canopy shape and this branch was blocking that view. There is a lower branch that I’m allowing to thicken up so the tree will be easier to climb on. Once it’s thick enough, I’ll cut it back as well for a lovely little foot-hold. Here’s the tree as of today so you can see it beginning to take shape.
This young lady has been in the ground for a little over two years now. The original branch was in a pot for about two years before I found a nice cozy home for it to live. Last year, the thing went crazy and grew more than double its size in about three months! Read about that madness here. The branches just shot straight up to the heavens. Take a look.
It’s so amazing to see this tree take shape as I’ve always wondered how it grew so wide and stout. Every season brings dramatic changes and a great deal of trunk thickening. It’s rare to see trees develop so quickly. Typically when you plant a tree, you’re planting it for your children to sit under, not you.
But enough about my tree, let’s get back to yours.
You’ll want to make the cut just slightly above the surface of the larger source branch so that the bark can grow around the wound in time and seal the area completely. Too far up and the wound will never seal, too far down and you can damage the vascular structure main branch. Both can leave the tree susceptible to rot and infection. Here’s a detail of the trunk of one of the Balboa Park specimens.
Notice that the lower branch cut was done slightly too far away from the main trunk? That’s no good. The bark will never heal over it in time for it to avoid rotting and harboring harmful pests. It’s already showing signs of this and can eventually become a serious weak spot for that large and heavy trunk. A ticking time bomb if this tree were planted close to a house or over a parked car! Oh, the humanity!
The one above it is slightly better and already on the road to being sealed up completely, however it is also showing signs of decomposition. This is why it’s always best to do the major pruning while the tree is still young or the newer branches are just developing. You can better avoid later cuts that can really impact the health of the tree. Bonsai training really helps one to hone these “fortune telling” types of early pruning. But that’s a whole other post Daniel-san so wax on y’all.
As for our cut, take note in the image below of the rather distinct separation of the branch to be removed and the larger branch that it’s attached to. This line is important for a good clean cut that will heal rather quickly.
Everything below the red line should remain intact for the wound to heal properly. So the cut should be made in a straight line across the branch at the highest point above this imaginary red line.
But before we can do that, make certain that you clean all of your cutting tools and then wipe the blades down with rubbing alcohol! If you don’t, the host, the cutting, as well as your tools, will suffer. Disease and bacteria can carry on to other plants via these tools.
Once everything is sterilized and clean, begin cutting as cleanly as you can muster. The smoother the cut, the faster the healing process can begin.
Below is the result of this minor tree surgery. Were this a larger project with multiple cuts I would’ve waited for a winter pruning, when the tree is dormant and the sugars are stored safely down in it’s roots. However, I should note that winter dormancy is a relative term in sunny and warm San Diego.
Not too shabby! New evidence (relatively new) shows that pruning sealer is wholly unnecessary and can actually cause more harm than good by trapping in harmful material. Just leave it alone and the tree will take care of the rest. If you must intervene (because that’s the type of person you are) then you can provide it with some makeshift shade to protect it from the sun while it heals. As the branch thickens the bark will grow over this wound and seal it up altogether. With a healthy and vigorous tree such as this one, it shouldn’t take more than a year to be completely healed. After a few years, all traces will be gone completely.
3) Attacking the Clones:
Above is the branch we just removed. These next few steps are critical for getting the branch to form roots before succumbing to rot (and possibly depression). We have no more need for any of those lovely green leaves as they will drop off long before you pot this baby anyways. The newer green growth at the tips of the branches will also wither away before a single root forms, so now is the time to remove all of it so that the sugars remain in the core of the branch and are not wasted on material that will die off anyways. Plus, in the dark, there isn’t much photosynthesis going on anyways. We’ll start off by removing the green new growth.
You can see in the above photo that on the left is the fresh newly formed green branch and to the right there are flecks of brown. That shows that the older growth is becoming woody (having woody parts : rich in xylem and associated structures). The latter is what is going to survive the next few steps because it has enough xylem to survive this rather dramatic and brutal attack (poor lil’ fella). The former lacks the structure to survive. It is weak and lacks the moral fiber. To bad, so sad.
Once this is complete, the next weak link in the chain are the leaves. Not a single one will survive the next stage of propagation, so those too must go! This can easily be accomplished with this species by applying a gentle downward pull at the base of the stem so that they will snap cleanly off.
While you may feel that this is waste of green loveliness, rest easy; all of those leaves will make an excellent nutritional addition to you composting pile!! Huzzah to nitrogen! So save those leaves y’all.
And here’s the final product! A completely naked coastal coral branch. I did leave the smallest branch with a few tiny leaf buds just to give it a glimmer of hope for the future. Emotional pandering is key in successful gardening.
This next step will seem very counter-intuitive, but bear with me. This is the key to success here that was prominent in the long lost PDF I mentioned earlier. This is the secret. Shhh.
4) Teetotalism; Time to dry out:
This was why I was having such poor luck propagating the smaller clippings. I cut them off of the tree, slapped them in rooting hormone and then stuck them in my little green fuzzy cubes of failure. The rotted because I failed to allow time for the cuts to dry up.
The process takes about two to three weeks and involves that cool dark place that I listed in the beginning of this article. We don’t have basements here in San Diego, so I have to settle for the garage but any dark, dry and cool spot will work fine. Here’s a photo of the optimal space for storage…
You want all those cut ends to dry up and you want the sugars to stop flowing. It’s those sugars that will form the new roots once you get this fella into the pot. You also want to store it upright so that the thicker portion of the branch is on the ground. The same orientation that you will be planting it in a few weeks. Here’s mine patiently waiting.
That’s all you can do for now. The big waiting game. I’ll see you in three weeks!
5) The Final Surgery:
This is that last step before planting your clone and requires a wee bit of surgery so get your hands steady. In this step we’ll be using the razor blade and, of course, we want to clean it with our rubbing alcohol before proceeding!!
We need to make some slight incisions along the length of the base of the branch to provide room for the new root nodes to form. This part is also critical as we do not want to cut into the vascular cambium, but just the bark. Here’s a diagram to help you know the difference:
Cutting into the cambium can cause issues with the vascular properties of the trunk and root nodes will not form at all because the tree will read this as a wound it needs to heal and seal it up with those stored sugars we were talking about earlier. Just a slight score into the bark will do the trick. All the way around the branch and long enough to score the entire section that you wish to bury in the soil. For this branch, I’ll just do a few inches.
If you have rooting hormones, now is a good time to add it to the scores you’ve just made along the branch. It’s not essential for success, but does increase your root structure and cut back on the time it’ll take for roots to form. If you don’t have any rooting hormone, don’t sweat it! You can always make your own willow water which will work like a dream and costs you nothing but time. I’ve also heard that cinnamon can be used as a rooting hormone substitute although I have no experience with this. Does anyone out there have good rooting hormone recipes they’d like to share? I’d love to hear them!!
Again, not essential to the task, but it will speed up the process.
6) It’s all in the Soil:
Now that your clone is fully prepared, it’s time to plant it into a 3-5 gallon pot so that it can begin to take root. I use a 50/50 ratio of pumice to rich organic sandy soil. This provides ample nutrients, water retention as well as excellent drainage. Premix your soil ahead of time in the pot you’ll be using so that you have the perfect amount all ready to go. If you only have access to bagged potting soil, that will work as well because the coastal coral is rather forgiving.
You’ll want to bury the branch enough into the pot so it will remain stable and not flop about. I’ve added some support sticks in the past so that I only had to bury the few inches that I scored with the razor blade. If the branch is too far in and you plan on making this into a bonsai, you’ll always have that thick central column to deal with as well as trouble forming a good root flare at the base. If you plan on putting it into the ground, it doesn’t really matter that much.
Now you simply place your branch into the soil and loosely pack it around the “trunk”. Give it a good slow soaking to allow the soil to settle a bit and place the pot in a warm sunny spot in your yard. Easy peezy.
It’s important to let the soil dry out completely in between watering during this waiting stage. Too much water will cause the branch to rot and it doesn’t have any roots to take up water yet anyways. In about three to five weeks, you should begin to see little green buds forming and then you can water it more regularly.
Once this occurs, the leaves will come in super fast and the tree will begin taking off. Here what the growth looks like during a two week period…
Crazy fast right?
If you leave it in the pot, it will get thirsty often and will need at least weekly watering, depending on the weather. If you plan on putting it in the ground* it should require less care after it’s been well established. Fertilize it in the early spring and it will grow faster than you’d expect!!
*NOTE: If you plant this species in the ground, please be aware of its location! Too close to a structure or above sewage pipes can be a costly mistake to make. The roots of this (and many other trees) can be fast growing and invasive to say the least. Take the time to find a proper safe place for this baby to live. The coastal coral is a sun loving, medium sized tree, so it won’t get too large and should be easy to find a home for. Also of note is that in most climates, it will act as a deciduous tree and drop it’s leaves seasonally. In San Diego, it’s hit or miss regarding this behavior and my leaves seldom drop. Again, the host plant will best determine the traits of the clone so be aware during field collection.
Well folks, there you have it! An extremely long-winded and detailed account on how to best propagate the lovely coastal coral tree, or erythrina caffra. Again, I wanted to provide a full account on this process seeing as no other one seems to exist out there. I’ve done this about four times and each and every time it has worked like a dream. Zero failure rate is a rare trait when it comes to plant propagation so take heed ye heathens!
I hope this helps to encourage more people to experiment with this fascinating species and please share your stories with me!! I want to hear you successes as well as your your near misses. Until then, Mind Your Dirt!