Rhododenron Impeditum and Chojubai Red Quince

[JonW]

Maybe a bit early in the Spring to share - flowers aren't quite open yet, but I'm excited about these two. Actually, the rhodo doesn't have many flower buds which is probably good - I want it to just grow and gain vigor, but I don't know if I would have been able to push myself to remove any flowers.

Rhododendron Impeditum gets small, blue/purple flowers that cover the canopy. As you can see, the foliage is tiny, smaller than Azalea, and the leaves are very fragrant. Rhododendron foliage tends to be fuller than Azaleas as well. Impeditum can be a fickle variety. I just transitioned this one from a nursery pot with organic barky-compost to 1/8th inch pumice. I removed most of the organic soil but left the main root ball because these often don't respond well to full bare rooting in my experience. Despite being slow growers, this jumped into new growth after the repot, which gives me some confidence it will survive this first step in transitioning to bonsai, and grow roots into the pumice. I did some cleaning and removed dead and low, weak branches, but won't do any pruning until next year - I want it to push as much root as possible. Its in a 10-inch pond basket, so plenty of space for a few years. I plan to remove 25-50% of the remaining organic soil with each repot, so it will take a number of years, but the soil looked decent and there was a nicely shaped nebari of very fine roots. Its a twin-trunk and has some trifurcations/whirls that I will have to address in the future. If you can transition it to bonsai soil, I think this is a really nice variety for bonsai due to its small leaves and flowers.

I up-potted the chojubai in the fall, adding some 1/8th inch pumice. Its a really good start for a trunk since these things take so long to caliper. I'm looking forward to many years of enjoying the flowers while I do some clip-and-grow.

The top-dressing on both trees is sphagnum moss with dried green moss, and Jobe's organic fertilizer.

 

[Deep Sea Diver]

Good You are braver then me, putting a Rhododendron Imp in a pond basket with a combo of its old media and pumice.
A couple questions if you have time.

Why did you chose to leave any old media? Why pumice? Finally what advantage would a pond basket have for a Rhody?

cheers
DSD sends

 

[JonW]

Good You are braver then me, putting a Rhododendron Imp in a pond basket with a combo of its old media and pumice.
A couple questions if you have time.

Why did you chose to leave any old media? Why pumice? Finally what advantage would a pond basket have for a Rhody?

cheers
DSD sends

Good questions.

I didn't leave the old, organic media out of bravery but caution. Although caution can be as dangerous as bravery (or lack of regard for the plants safety for that matter!). As I was removing old soil, a lot of root was breaking away, and rhody's, especially impeditum, can be finicky. The soil in the bottom fell away pretty easily and I was left with a nice, thin / flat root ball - I made the judgement that it would be too risk to remove more soil, and consequently more root. I tend to bare root anything I'm transitioning from nursey to bonsai material, and I have to admit, I usually have judgements when I see trees with a mix of old organic soil in the root all and bonsai soil around the outside since this could cause the root ball to be too wet or the bonsai soil to be too dry. However, having said that, I know a lot of people never bare root a tree and it is also fairly common practice to do what I did with this rhody. So I figured I'd experiment with that approach.

Why pumice - I really like pumice. Over the years, I've moved to using more and more of it. I know kanuma is the Japanese gold-standard for azalea, and I've never looked into accessing it, but I'm sure its more expensive than I'd be willing to pay. Pumice encourages great roots in a lot of plants and doesn't really break down. The finer, 8th inch pumice seems to work well for plants that want a bit more water, have finer roots, are in smaller containers or a mixture of the above. Since Rhododendron don't want to dry, but like good drainage, I thought it would work. Since most of my plants are dwarf varieties, the finer media works well. I have both 1/8 and 3/16 (I bought about 7-gallons of each and have a little left after repotting everything) - I found 1/4 inch media to be too big for nice, fine roots, at least for the trees I have. Also, most of my trees are in development - I sold a lot of my older trees last summer for varieties that I was more interested in (more compact varieties that fit my space better). I know some people prefer akadama for refinement. I don't know if I will start adding akadama to pumice in some of my trees when they get further along, but this year, I used mostly pumice.

Pond basket - I got some pond baskets and air pruning pots for some of the trees I wanted to develop this year. To be honest, I didn't think much about putting the rhody in the pond basket aside from it being the right size, but afterwards, I was thinking it might not be much of an advantage since rhody's have such fine roots, and maybe it would even be detrimental if the sides dry out too quickly, since rhody's like just the right amount of moisture. But we will see - I have a drip system that has worked really well for me for several years, so I think I can hone in on the right amount of moisture, possibly even misting the sides of the basket.

 

[Ohmy222]

I love pond baskets, they get the best root bases. To your point though, Azaleas (and assume Rhododendrons) have perfectly fine roots to start with so the benefit is probably less. The only downside to pond baskets to me is they are taller than they are wide which isn't ideal if you want that pancake nebari. The air pruning is great and you have no circling roots. I have thinned out my azaleas over the last couple of years but used to have a lot of them. I never saw the benefit of kanuma and I am not certain they didn't hurt my trees. Mine seemed better with a mix of akadama and pumice. I have a few in the ground and they are probably 80% perlite/20% dirt and they seem to be fine. Azaleas are the only thing I really prefer to grow in the ground as the roots won't take off on you like a normally tree would.

 

[JonW]

I love pond baskets, they get the best root bases. To your point though, Azaleas (and assume Rhododendrons) have perfectly fine roots to start with so the benefit is probably less. The only downside to pond baskets to me is they are taller than they are wide which isn't ideal if you want that pancake nebari. The air pruning is great and you have no circling roots. I have thinned out my azaleas over the last couple of years but used to have a lot of them. I never saw the benefit of kanuma and I am not certain they didn't hurt my trees. Mine seemed better with a mix of akadama and pumice. I have a few in the ground and they are probably 80% perlite/20% dirt and they seem to be fine. Azaleas are the only thing I really prefer to grow in the ground as the roots won't take off on you like a normally tree would.

Thanks for the input and feedback! I have a number of azalea and other small leaf rhododendron (purple gem and ramapo) in my landscaping that I planted in a mix of composed bark and used or leftover bonsai soil (they hate the clay soil in my region). An azalea was frequently next on my priority list for bonsai, but never put one into bonsai training until this (I tend toward broadleaf deciduous).

I'm sure Anderson flats would have been better for a flat root base while giving the space to grow and air pruning that you also get from a pond basket or air pruning pot, but my space is limited and these trees are pretty early in development, so something deeper made more sense. Once I get some growth and structure in the plants (including rhody), I'll probably transition to a mica pot, but I'm guessing that will be in 3-5 years.

 

[hinmo24t]

Maybe a bit early in the Spring to share - flowers aren't quite open yet, but I'm excited about these two. Actually, the rhodo doesn't have many flower buds which is probably good - I want it to just grow and gain vigor, but I don't know if I would have been able to push myself to remove any flowers.

Rhododendron Impeditum gets small, blue/purple flowers that cover the canopy. As you can see, the foliage is tiny, smaller than Azalea, and the leaves are very fragrant. Rhododendron foliage tends to be fuller than Azaleas as well. Impeditum can be a fickle variety. I just transitioned this one from a nursery pot with organic barky-compost to 1/8th inch pumice. I removed most of the organic soil but left the main root ball because these often don't respond well to full bare rooting in my experience. Despite being slow growers, this jumped into new growth after the repot, which gives me some confidence it will survive this first step in transitioning to bonsai, and grow roots into the pumice. I did some cleaning and removed dead and low, weak branches, but won't do any pruning until next year - I want it to push as much root as possible. Its in a 10-inch pond basket, so plenty of space for a few years. I plan to remove 25-50% of the remaining organic soil with each repot, so it will take a number of years, but the soil looked decent and there was a nicely shaped nebari of very fine roots. Its a twin-trunk and has some trifurcations/whirls that I will have to address in the future. If you can transition it to bonsai soil, I think this is a really nice variety for bonsai due to its small leaves and flowers.

I up-potted the chojubai in the fall, adding some 1/8th inch pumice. Its a really good start for a trunk since these things take so long to caliper. I'm looking forward to many years of enjoying the flowers while I do some clip-and-grow.

The top-dressing on both trees is sphagnum moss with dried green moss, and Jobe's organic fertilizer.

that rhody type caught my eye at home depo the other day...very cool looking, good luck w it

im going to buy one or something i havent seen on here often. a vibrant purple or blue stemmed holly with smaller leaves than i see on the spiky holly usually. its a blue prince or purple something i forget but i think its claiming me after work, pre dog walk today. i have so many holly around that i think i will get it to berry out and fruit in winter

 

[JonW]

that rhody type caught my eye at home depo the other day...very cool looking, good luck w it

im going to buy one or something i havent seen on here often. a vibrant purple or blue stemmed holly with smaller leaves than i see on the spiky holly usually. its a blue prince or purple something i forget but i think its claiming me after work, pre dog walk today. i have so many holly around that i think i will get it to berry out and fruit in winter

I've seen some really pretty varieties of holly that almost look like boxwood until you get closer. I just searched blue prince and it looks like a nice compact/dwarf version of holly. Those types of plants - holly and pyracantha - can be pretty striking when they have their berries. I've never grow either in landscape or pot though. Post a pic of whatever you decide to pickup today!

 

[Deep Sea Diver]

Thanks for the rationale.

I’ll throw out a couple things for you to think about. Rhododendrons and azaleas (which are Rhodys actually) have similar fibrous, flat root balls. They each like to be moist, not wet, high in organic media with a high CEC. Root rot is the number one killer of both, with over fertilizing right up there.

Both prefer an organically oriented homogeneous media that will disperse moisture evenly. (This aids in checking soil moisture btw) That said I won’t get in a potting media differences discussion, yet you were correct to say that kanuma is the gold standard media, although 90/10% kanuma/pumice mix been put forward as a better, more friable alternative... and akadama has been used too. In addition, there are plenty of other medias that rhodys will grow well in. A recent BN survey on media used for azaleas showed this vividly, although kanuma was by far the most used component in azalea media. The key point is to use homogeneous organic oriented media for best growth.

As you said, having two separate dissimilar medias in one pot is asking for trouble. Particularly with Rhody species. As you so properly noted the species you are using is finicky. I have a couple of these right out front and agree with you on this point.

Finally, planting in a pond basket for Rhody species is not such a good idea. Their roots should be cool and moist throughout. Pond baskets are not meant to keep roots cool and moist throughout, but to drain quickly. That’s why plastic pots aren’t so good for Rhodys either. The outer roots get fried on warm days. Pond baskets are great for conifers and other trees though!

That said, I wish you well on your experiment. Please keep us posted on your progress On both your Rhody and the chojubai!

cheers
DSD sends

 

[just.wing.it]

That Rhodo is so cool!

 

[JonW]

Thanks for the rationale.

I’ll throw out a couple things for you to think about. Rhododendrons and azaleas (which are Rhodys actually) have similar fibrous, flat root balls. They each like to be moist, not wet, high in organic media with a high CEC. Root rot is the number one killer of both, with over fertilizing right up there.

Both prefer an organically oriented homogeneous media that will disperse moisture evenly. (This aids in checking soil moisture btw) That said I won’t get in a potting media differences discussion, yet you were correct to say that kanuma is the gold standard media, although 90/10% kanuma/pumice mix been put forward as a better, more friable alternative... and akadama has been used too. In addition, there are plenty of other medias that rhodys will grow well in. A recent BN survey on media used for azaleas showed this vividly, although kanuma was by far the most used component in azalea media. The key point is to use homogeneous organic oriented media for best growth.

As you said, having two separate dissimilar medias in one pot is asking for trouble. Particularly with Rhody species. As you so properly noted the species you are using is finicky. I have a couple of these right out front and agree with you on this point.

Finally, planting in a pond basket for Rhody species is not such a good idea. Their roots should be cool and moist throughout. Pond baskets are not meant to keep roots cool and moist throughout, but to drain quickly. That’s why plastic pots aren’t so good for Rhodys either. The outer roots get fried on warm days. Pond baskets are great for conifers and other trees though!

That said, I wish you well on your experiment. Please keep us posted on your progress On both your Rhody and the chojubai!

cheers
DSD sends

Thanks for the insights. I do plan on using humic acid to increase CEC and I assume it is also somewhat lower in terms of PH, which I know rhododendron's prefer. I haven't seen many people using organic material for bonsai including for azalea, but I can see the benefit in terms of even moisture. I don't love the idea of using a medium that breaks down though. I am aware that Azaleas are a type of rhody with the main difference, at least technically, being the flowers and stamen, and that they have shallow, fibrous roots. I figured those roots might be sensitive to over-fertilization with synthetics, but I appreciate the warning - I will be cautious. In the past few years, I've backed off of using the higher end of the suggested concentration noticing that certain more sensitive plants prefer it (not bonsai, but orchid roots react poorly to excessive fertilizer).

I'll post updates later this summer, whether or not the rhody fares well.

 

[JonW]

That Rhodo is so cool!

I know! I wanted one for a few years and I had credit to rhododendrondirect.com, so I went for the largest size they had in stock. I figured I could live with its lack of caliper since it was a reasonable price and unique variety.

Your GD Steely lightening bolt image is so cool too! I'm a big dead-head. I always debate with my uncle who should really carry the torch for Jerry. He likes Warren Haynes. I think Haynes is too heavy sounding and more blues/Southern rock. I loved Trey on the 50th Anniversary Tour and John Mayer has sounded pretty good even though I don't love his old tunes etc.

 

[Underdog]

That Rhodo is so cool!

Agree! I have a Ramapo but twice or bigger leaves. Nice.

 

[JonW]

Agree! I have a Ramapo but twice or bigger leaves. Nice.

I have a Ramapo in ground and 3 Purple Gem. Their leaves are many times larger, but still pretty nice and small. They are my favorite for landscaping in a small space. As evergreens, they have some winter interest. They bloom early-ish, and I also have Hydrangea Macrophropylla in the same area that don't look so interesting in the winter, but they bloom in summer. The combo gives nice coverage year round!

The Rhodo Impeditum is growing very vigorously, but no flowers. Below are some pics of the Quince. The first flower is already spent - I'm not sure if I will have more than a couple flowers open at a time, but it looks nice with the bark that is starting to get gnarly, the tiny green leaves ad bright red flowers.

 

[JonW]

Guess I was wrong about only a couple flowers opening at a time...

 

[JonW]

Not an exciting update, but the rhodie is doing well and put on a ton of growth.

 

[Underdog]

Had to have one. Plant lust... paid too much for a 1 gallon bag coming in a week or two. LOL

 

[JonW]

Had to have one. Plant lust... paid too much for a 1 gallon bag coming in a week or two. LOL

I got this one from rhododendron direct. Keep us updated!

 

[Underdog]

I got this one from rhododendron direct. Keep us updated!

https://plantlust.com/ you folk thought I made that name up LOL It was $23 plus 15 sh for 1 gal.