Challenges with hardwood cuttings

[andrewiles]

Hey bonsai masters,

I trying to root some cuttings for the first time. Looking for some advice, as I'm seeing some mold :-(

• Following https://crfg.org/wp-content/uploads/Propagation-by-Cuttings-Presentation.pdf. At the pre-rooting stage, so slide 4. This approach was appealing to me because I can see if I'm making progress early on with the bags.
• Since the cuttings are in bags, humidity is at 100%. Temps are kept around 80 degrees with a heating pad inside my house.
• I tried a few different trees of different species, branch diameters and 1-year vs. 2-year old wood. All of the trees were outside and dormant. Larch, dawn redwood, acer palmatum.
• The cuttings were taken about 1.5 weeks ago.
• I used a root hormone gel, pictured.

The problem is that I'm starting to see some mold. It's the white film, esp, on the right, in the attached picture. I did not use a fungicide, in part because the rooting hormones usually have some included. I'm not seeing any roots yet. Seems consistent across the different bags I put together.

I'll keep these going but not optimistic. I'll also start another batch. I'll try adding some fungicide to one bag and I'll try to reduce the humidity in another, perhaps by leaving the bag slightly open. And in a third I'll skip the bag and go right to a vermiculite plastic cup.

Any other advice?

 

[River's Edge]

Fresh air is important for controlling mold.
So one approach is to open the bags occasionally to exchange gases.
Second approach is to use a larger cover or bag to increase the volume of humid air and decrease the chance of mold!
Third approach a mild fungicidal rinse such as hydrogen peroxide solution in water sprayed occasionally to control mold.
Fourth approach, recognize that mold on the top cut will not adversely affect the leaves lower down when they emerge. Spray hydrogen peroxide mix on it and forget about it.
Fifth seal the top for better results if you did not do that.
Sixth, refer to Dirr and Heuser " The reference Manual for Woody plant Propagation " for further advice on specific approaches and species.

 

[andrewiles]

Very helpful. Would you say that ~100% humidity is fine, as long as the air can circulate. Or is the desired impact of the circulation slightly lower humidity?

 

[leatherback]

looking at your cuttings.. Are these the top or the bottom of the cuttings? To me they look like the bottom, but considering they are not in substrate..

 

[andrewiles]

They are the bottom. See slide 4 of https://crfg.org/wp-content/uploads/Propagation-by-Cuttings-Presentation.pdf. I'm going to put them in a substrate after roots begin to show.

 

[Wires_Guy_wires]

I disagree with slide 4 on multiple levels.
They should note or should have noted that - in general - most plants put out some foliage before they start rooting. Some species can root without foliage, if they stored enough energy and if fungus doesn't start munching on the wood and carbohydrates. Since I see little callous growth, I think your cuttings are in the group that needs foliage and active respiration to produce roots.

Putting them in a substrate (bagged or not) will benefit both the sap flow (so they know where to produce roots instead of just trying to root at the most damp parts), and it'll give them room to produce some foliage that could serve as a generator for growth if there's sufficient light.

It's important when taking cuttings, to keep in mind that every species and family and sometimes even cultivars of plants have their own perfect technique. I've been digging into cherries for instance, and some root only without hormones, others root only with hormones, some root with NAA and not with IBA, some need a combination, and others don't root at all from hardwood cuttings. While general cutting techniques all boil down to the same thing: take a branch, root it in some kind of substrate.. The success rate depends on the fine tweaks you do yourself. You can experiment, which I fully endorse, but usually if you dig a little in literature you can find that most of that experimenting has been done in the 1980's already when one could get a biology degree by doing a study on rooting behavior of commercial stock - and it shows; there are a lot of studies on rooting behavior of cuttings from that era, and a LOT of those studies wouldn't meet current scientific demands by miles. But those studies are a good starting point for further exploration.

The ones in the document you're showing are mostly figs, I'm rooting those in water because I heard it was easier that way. It seems to be true. I have a 40% rooting rate in peat moss, but a 100% in plain old tap water.

 

[keri-wms]

I wonder if dipping them in lime-sulfer before bagging might be one old school solution worth trying on a small number? Smelly though!

 

[Wires_Guy_wires]

I wonder if dipping them in lime-sulfer before bagging might be one old school solution worth trying on a small number? Smelly though!

I think that it might be too strong in many cases. Not sure how diluted it should be. Some peroxide can help, a low pH and free radical oxygen can do some disinfection, the low pH also helps rooting! Activated charcoal can be beneficial too, because it captures some inhibitory molecules that come from wounds (and those molecules also signal some fungi to attack).

 

[sorce]

Pandemic Propagators!
Lol.
There is a surge of Pandemic Potters.

Just bringing that up to accent the fact that there is absolutely no shortage of tutorials etc out there meant to ONLY keep you busy.

I have to ask, what are you doing this for?

If it's to stay busy, cheers.

If it's not to pass time I wouldn't put so much effort into it.

For Bonsai....you want to cull...cull.... cull.

A cutting that takes with no more than cut and a plop, is also going to be the bonsai that takes to repotting well.

Needing little more than that for success as bonsai, using anything that takes more time and effort, is just creating a bane of a tree for you or someone else, forever!

Don't create a bane.

Cut and Plop Bonsai.

Sorce

 

[andrewiles]

You're on to it: pandemic propagation. Stuck at home during pacific northwest winters gives rise to all matter of strange behavior.

I'm really just trying to learn. Since I have some time and some random branches outside I figure I would play around. If nothing takes it's no big loss.

That said, I really should be able to follow simple instructions on the internet and get things to grow. So I'll keep at it. It's knowledge I can use later.

I cleaned off the fungus, added some fungicide and they are back on the heat. To @Wires_Guy_wires point, I put some of them directly in substrate. Some are starting to leaf out, so hopefully I that will trigger root growth. I'll update this thread on what I find.

 

[BonjourBonsai]

They are the bottom. See slide 4 of https://crfg.org/wp-content/uploads/Propagation-by-Cuttings-Presentation.pdf. I'm going to put them in a substrate after roots begin to show

The presentation shows how to root fig cuttings which will root very easily. Stick the right end in sand and keep it watered, no need for heat. I tried a similar method to the one shown in the presentation with JM and juniper cuttings. I had 0% success rate with JM and about 75% with junipers. This year, i am trying junipers again but without bottom heat. I expect similar success but over longer time.

Give the cuttings some fresh air each day. That would help to control fungus.

 

[AJL]

You're on to it: pandemic propagation. Stuck at home during pacific northwest winters gives rise to all matter of strange behavior.

I'm really just trying to learn. Since I have some time and some random branches outside I figure I would play around. If nothing takes it's no big loss.

That said, I really should be able to follow simple instructions on the internet and get things to grow. So I'll keep at it. It's knowledge I can use later.

I cleaned off the fungus, added some fungicide and they are back on the heat. To @Wires_Guy_wires point, I put some of them directly in substrate. Some are starting to leaf out, so hopefully I that will trigger root growth. I'll update this thread on what I find.

Sorry if if Ive missed it but what species are you trying to root from hardwood cuttings? Im not familiar with your climate zone but here in Britain most hardwood cuttings are normally stuck into the ground to roughly half their depth in autumn and left to get on with it outdoors, with minimal cover or protection. Theyre not in leaf so the tops dont need to be kept in such a saturated humid enclosed environment, which is causing you the mould problems. Better ventilation will help

 

[leatherback]

They are the bottom. See slide 4 of https://crfg.org/wp-content/uploads/Propagation-by-Cuttings-Presentation.pdf. I'm going to put them in a substrate after roots begin to show.

The document you linked seems to be non-consistent.

most hardwood cuttings are normally stuck into the ground to roughly half their depth in autumn and left to get on with it outdoors, with minimal cover or protection.

Yes, here too.

It is important to realize the range of conditions needed to root from species to species. Find the method for the species/cultivar you are trying to root. AJL had good generic method for many species from temperate regions.

 

[andrewiles]

@AJL I'm trying a bunch of things: a vine maple, several different larches, several dawn redwoods and several BCs. Basically, cuttings from a bunch of deciduous nursery plants I've acquired over the last year. Some 1 year and some 2 year old wood. Some with and without hormone. Some pre-rooting in bags, some in vermiculite, some in perlite. All indoors and on heat/humidity right now.

Yeah, I know most folks just stick them outside and wait for spring, but I wanted to see if I can induce any growth faster while trying some different approaches. Honestly, the internet is not terribly consistent on what works. So for me, this is a chance to experiment and learn what works or doesn't for my situation. I get satisfaction from the experience.

To your point, I'll also place some cuttings outside and let spring come naturally. And yeah, I'm aware of some specific suggestions for the species I'm working with. I'm just trying some generic things first.

Thanks for all the feedback. This is such a great forum.

 

[AJL]

The internet seems to be full of ''helpful '' propagation tips from hobby growers who dont have any real horticultural credentials!
So youre trying to propagate hardy plants outdoors at 80 degreesF- where did you get that advice from ? You are almost cooking them LOL!!
The optimum temp on a propagating mist bench for hardy nursery stock softwood and semiripe cuttings is only @21c (70 degrees F)
You are better sticking to advice and practices followed by growers and professionals. eg check out
https://www.rhs.org.uk/advice/profile?pid=387 for good basic proven methods, unless you just want to experiment and have fun!!
Heres a hardwood cutting of Lonicera nitida planted in the ground November 2019, and just left to root itself!

 

[BonjourBonsai]

the internet is not terribly consistent on what works.

Understatement of the year!

 

[andrewiles]

Quick update. The cuttings outside are still hibernating. I kept some inside in vermiculite and they have sprouted. No visible roots yet though, so may be a lost cause. Both BC and DR cuttings have grown leaves at least