May 4, 2022

Invasive Japanese Honeysuckle (Lonicera japonica & related species) for Bonsai

            It's May which means that trees here in Ohio have been slowly waking up and spring is creeping northward! This also means we just passed the best time of year to root prune trees for repotting or for collecting wild trees to train as bonsai. Although collecting wild bonsai is an exciting method to gather prebonsai, many bonsai artists are unable to utilize this source of bonsai material due to a lack of access to public land where tree collection is permitted or some novices with such access may just be too intimidated by the prospects of killing trees during transplanting. One solution to both of these issues is to coordinate with local governments on removing unwanted, invasive species and attempt to utilize those species for bonsai. This three-part article series will cover a story of local collaboration in Ohio doing just that. I am happy to report that the Columbus Metro Parks now have a few less invasive Japanese Honeysuckle to worry about and the members of the Columbus Bonsai Society were allowed free access to digging wild bonsai material from our local forests. Additionally, this event allowed interested CBS members to learn about digging wild trees in a guided and hands-on fashion while also practicing guilt-free on material that is limitless (invasive trees) which would otherwise be destroyed during the city government's efforts to maintain native ecosystems.

            Today's portion of this 3-part series will focus on the invasive Japanese Honeysuckle and related Lonicera species which we collected at the CBS Honeysuckle Dig event last month. Below you will find specimen bonsai showing the potential of these species and observations from the woods as to which honeysuckle trees may make good bonsai. Future installments will cover the club dig event itself including essential information on the basics of what tools are needed and how to dig from the deciduous forests of Ohio. Finally, the last article in the series will cover other invasive species of the United States (with links to resources for other locations around the world), highlighting those which have known bonsai potential.

Sections

  1. Invasive Japanese Honeysuckle (Lonicera japonica & related species.) for Bonsai (this time)
    1. Examples of Honeysuckle Bonsai
    2. Identifying Candidate Honeysuckle for Bonsai
    3. Observations & Comments on their Suitability as Bonsai
      1. Ability to Ramify
      2. Response to Trunk Chops
      3. Wood Durability/Deadwood
      4. Wiring Branches
      5. Shallow Root Systems
  2. Combining Yamadori Education with Invasive Plant Removal - A CBS Collaboration with the Columbus Metro Parks (next time)
  3. Invasive Trees & Shrubs with Known Bonsai Potential (next next time)
  4. Blog Announcements
  5. References

This honeysuckle was collected by the late Nick Lenz and has been styled and cared for by Nick's student, Andy Rutledge (Source). The face carved into the tree fits nicely with Nick Lenz's signature macabre and fantastical style; you can see more examples of this style in an earlier article I wrote on the subject.

            Before we get started I want to make a quick aside on the benefits of using invasive species for bonsai. Above I already outlined how they are beneficial to bonsai artists - a free and endless supply of practice material. However, they would also be beneficial to the environment! First, removing invasive species from natural ecosystems makes room in those ecosystems for native plants to attempt to establish. Second, honeysuckle or other invasive species which is pruned to a 1-2 foot tall bonsai will produce significantly fewer seeds than a full-grown 8-foot tall honeysuckle left to its own devices in the forest understory or along the highway. Furthermore, as outlined in my older article "The Cost of Sex", flower and fruit buds can easily be removed to prevent the seeds from entering the environment, thereby making the invasive potential of such species as bonsai negligible.

I. Examples of Honeysuckle Bonsai and Niwaki

            First, belonging to the same genus does not automatically make every species equally suitable for bonsai (see the variety of ficus and maple species), it's therefore good practice to be specific about the invasive honeysuckle species which we can find easily in the US. The most common invasive US honeysuckle species listed below all originate from Asia and Europe, replicate prolifically outside their native range, and are especially hard to cull from an ecosystem once they escape cultivation, thus they are considered invasive in the US and many other areas (Source, Source). Explore the links for each species to learn more about their identification, origin, history, and current distribution. Some of the species below are also similar enough to produce hybrids (Source).
            Perhaps because of the endless supply of invasive honeysuckle hiding in plain sight in North America, the above species are largely overlooked by bonsai artists and these trees are not common in club shows or larger regional/national shows despite their abundance. However, there is a handful of honeysuckle bonsai that are likely examples of the invasive species or similar enough in growth habit that their existence supports the exploration of these species. Andy Rutledge's honeysuckle pictured at the top of the article is one such specimen of unknown species but certainly collected from the US origin, making it likely one of the invasive species. (In botany, flowers are usually needed to make an exact identification). Other supporting evidence of the potential of the Lonicera genus for bonsai is found on Walter Pall's blog, where he has numerous different posts showing the collection and refinement of a variety of European honeysuckle species, some of which are the same species that are invasive in parts of the US (Source). A third bonsai professional - Bill Valvanis - has also tried his hand at US-origin collected honeysuckle to great effect. His tree is also pictured below (Source).
Lonicera periclymenum owned and styled by Walter Pall of Germany. This species can also be found in the US but less commonly. Source

Bill Valvanis's unknown Lonicera species in flower. Source

Bill Valvanis's unknown Lonicera species in fruit. Source

            In addition to the use of honeysuckle as bonsai, I also recently met an artist and landscape enthusiast in Columbus who has pruned several invasive honeysuckle volunteers as landscape-styled trees, or "niwaki" as they are called in Japan. It's nice to see that with a little attention to detail, unwanted weeds can become a feature of the garden! See the photos from Jim's garden below. He largely created these forms via hedge and topiary pruning methods and Jim is now becoming interested in bonsai and joining the local club.

Here you see the waterfall-esque Japanese honeysuckle next to the path in Jim's garden.

It's not quite as magnificent in winter, however, its nude state allows us to see how easily the species ramifies, as we will discuss later in the article.

II. Identifying Candidate Wild Honeysuckle for Bonsai

            As with identifying candidate deciduous yamadori, our hunt for honeysuckle yamadori hinges on the fact that we can prune back the trunk to bring the focus of the future design to interesting points such as the root spread, deadwood scars, movement in the trunk, and possibly taper (summarized below). Honeysuckles in Ohio often grow in forest understories, resulting in their foliage being too far from the trunk to be used in the initial design. Therefore, this type of chopping and regrowing is likely required to start the bonsai process for honeysuckles that have already built captivating trunks, rather than looking for naturally stunted honeysuckle which would be much rarer to find. The below trees were ones I scouted in March before spring started here in Ohio - the underbrush of the forest is much easier to navigate at this time of year! 

Look for the following traits below and imagine how you can design a future tree from the foundation that is these Honeysuckle trunks.
  1. Root spread ("nebari" in Japanese)
  2. Trunk movement
  3. Trunk taper + low branching
  4. Deadwood and scaring

Specimen neighboring streams and rivers often have interesting surface roots exposed, however digging them up will destabilize the soil on the bank, leading to erosion. If other options are available, it is better to leave these.

There are many honeysuckle examples where the trunks grow straight. Certainly, these can be used, but I always tell people I don't want my whole collection to be straight trees. Search around for a tree that inspires you!

Honeysuckles often form clumps which result in trunk swelling at the base. This can start as an awkward ball shape but looks more natural with age such as this example.

The fact that so many honeysuckles in the forest understory grow straight makes this one unique. It could become a slant style.

There are small baby honeysuckle with some interesting shapes too if you're into much smaller bonsai.

This tree has attractive surface roots, structural branches, and trunk movement.

Another one with trunk movement, and low branch options. 

In our deciduous forests, it is common for trees and branches to fall on others, helping to shape them. Here deadwood was created and both the top and bottom pieces of the trunk are alive. It could become a raft or semi-cascade!

Another living honeysuckle enduring after a tree fall.

III. Observations and Comments on Invasive US Honeysuckle's Bonsai Suitability

            Although we have already seen some honeysuckle bonsai above, let's distill observations of the specific invasive species specimen that may impact our use of them as bonsai.

IIIA. Ability to Ramify

            As shown in the pictures of the landscape styled Niwaki Japanese Honeysuckle, the species can easily grow dense branching when regularly pruned throughout spring and early summer especially.
A closeup of honeysuckle ramification in winter. In a bonsai, this would need some sorting out and thinning for aesthetic purposes.

IIIB. Response to Trunk Chops

            One ability I always look for in potential species for bonsai is their ability to bud back after a trunk chop or harsh pruning as we often have to do during styling bonsai. Species that do not bud back can still work but must be worked with more cautiously, such as by maintaining low branches on conifers when growing them from seed. This does not seem to be necessary for the Japanese honeysuckle and other invasive honeysuckles however as they are well-known for their ability to regrow from trunk chops. The only way to fully eradicate them is to remove the roots or apply herbicide directly to the chopped trunks.

Here we see a honeysuckle that was chopped back last summer and which sprouted new low branching before fall set in.

IIIC. Wood Durability/Deadwood

            The durability of honeysuckle deadwood is questionable. Due to their brittle wood, dead branches usually do not remain on the trunk for long, however, hollows seem to occur naturally in the wild with no ill effects on the trees. I have heard in a related concern that while honeysuckle can form callous, their callous tissue does not expand much so a large cut will never be fully hidden without carving or steps taken to avoid this sort of pruning.

This final raft-style honeysuckle also shows attractive deadwood hollows.

IIID. Wiring Branches

            An additional consideration for honeysuckles must be that the branches become brittle once they are thick! Wiring must be done mainly for young branches. Otherwise, you are better off employing clip and grow or perhaps guy-wiring.

IIIE. Root Systems

            Lastly, the prevalence of attractive surface roots was shown above in the photos from the forest, however, it is noteworthy to add that these honeysuckles were all very shallowly rooted and easy to dig! It may be due to their growing environment being a shady forest understory permitting moist conditions and not necessitating a large taproot, in combination with the brittle nature of the wood making large roots easy to break during the digging and prying process.

IV. Blog Announcements

V. References

Honeysuckle Introduced Species Observations in the US. (n.d.). INaturalist. Retrieved April 27, 2022, from https://www.inaturalist.org/observations?introduced&place_id=1&quality_grade=research&taxon_id=51874&view=species&iconic_taxa=Plantae
Lonicera japonica (Japanese honeysuckle). (n.d.). In Invasive Species Compendium. Retrieved May 4, 2022, from https://www.cabi.org/isc/datasheet/31191
Lonicera maackii (Amur honeysuckle). (n.d.). In Invasive Species Compendium. Retrieved May 4, 2022, from https://www.cabi.org/isc/datasheet/31192
Lonicera morrowii (Morrow’s honeysuckle). (n.d.). In Invasive Species Compendium. Retrieved May 4, 2022, from https://www.cabi.org/isc/datasheet/31193
Lonicera tatarica (Tatarian Honeysuckle). (n.d.). North Carolina Extension Gardener Plant Toolbox. Retrieved April 27, 2022, from https://plants.ces.ncsu.edu/plants/lonicera-tatarica/
Pall, W. (2008, June 14). Walter Pall Bonsai Adventures: Flowering honeysuckle, elm and maple. Walter Pall Bonsai Adventures. http://walter-pall-bonsai.blogspot.com/2008/06/flowering-honeysuckl-elm-and-maple.html
Rutledge, A. (n.d.). Artistic Foundations of Bonsai Design. Retrieved April 21, 2022, from https://andyrutledge.com/book/
Schoech, W. (2017, March 15). Honeysuckle Bonsai – Before & After (& One Small Bonus) | Bonsai Bark. https://bonsaibark.com/2017/03/15/honeysuckle-bonsai-before-after-one-small-bonus/

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