The Tropical Fruit Forum

Used ChatGPT to look into cultivation of a citrus variety that is obscure outside of Japan. Told it to search Japanese language web pages. Yielded much more informative results than my own searches in English.

Propagation Methods of 黄金柑 (Ōgonkan) – A Review of Japanese Sources

黄金柑 (Ōgonkan, also called Golden Orange or Ki-mikan) is a Japanese citrus variety known for its bright yellow rind and sweet, aromatic flesh. Japanese-language sources – including academic insights, industry publications, and government reports – consistently emphasize that citrus like Ōgonkan are primarily propagated by grafting onto hardy rootstocks, rather than by seed. Other propagation methods such as cuttings and air layering are possible but less common. Below is a summary of key findings on Ōgonkan propagation methods from Japanese sources, with a focus on seeds vs. grafting vs. other vegetative techniques.

Seed Propagation (実生繁殖)
   •   Seeds are present but not the preferred method: Ōgonkan fruits contain a few seeds (typically 3–4 per fruit). While these seeds can germinate and grow into new trees, commercial growers in Japan rarely use seed propagation for citrus. The Ehime Prefectural citrus Q&A explains that raising citrus from seed takes a long time to reach fruiting and runs the risk of yielding a plant with different traits than the parent . In other words, seedlings have a long juvenile period and may not come “true to type”, so they are generally avoided in favor of faster, more reliable methods.
   •   Polyembryony and nucellar seedlings: Like many citrus, Ōgonkan is polyembryonic, meaning a single seed can produce multiple embryos. Often, one embryo is sexual (zygotic) and the rest are nucellar embryos – clonal seedlings of the mother plant . Japanese sources note that polyembryonic citrus seeds tend to sprout many nucellar seedlings, which are genetically identical to the seed parent . This phenomenon has practical implications: even if grown from seed, Ōgonkan seedlings might be clones of the mother tree rather than new hybrids. For example, Kanagawa’s development of the hybrid Shōnan Gold suggests that one of the seedlings from an Ōgonkan × unshū mandarin cross was actually a nucellar (clone) Ōgonkan seedling. While breeders sometimes exploit nucellar seedlings for selecting variations, farmers typically do not propagate orchard trees from seeds due to the long wait for maturity and the unpredictability of getting a true hybrid or a clone .
   •   Use in breeding vs. commercial planting: In summary, seed propagation of Ōgonkan is mainly of interest for breeding or hobby growing, not for commercial orchard establishment. A hobbyist report notes that planting Ōgonkan seeds is feasible (with germination in a few weeks), but it took about 7 years for a loquat grown from seed to fruit, implying a similar wait for citrus. Commercial growers avoid this delay.

Grafting (接ぎ木)
   •   Dominant propagation method: All reviewed sources agree that grafting is the standard propagation method for Ōgonkan and other citrus in Japan . Grafting involves taking a bud or scion (枝接ぎ穂) from an existing Ōgonkan tree and uniting it with a separate rootstock plant. The rootstock is usually trifoliate orange (Poncirus trifoliata, カラタチ) or related hardy citrus, which confers vigor and disease resistance . The Ehime Prefecture’s guidance explicitly states that citrus propagation “usually uses grafting” and that seed propagation (実生) is “normally not used” due to the issues mentioned above .
   •   Advantages of grafting: Grafted trees have several benefits. The rootstock’s established root system can more efficiently uptake water and nutrients, leading to faster growth and earlier fruiting compared to seedlings . Grafting onto dwarfing rootstocks like trifoliate also keeps the tree smaller and more manageable, and ensures the fruit quality remains true to the scion variety. Japanese experts note that if citrus were grown on their own roots (as in cuttings or seedling trees), they often become too vigorous and take longer to bear fruit. By using grafting, growers can have Ōgonkan trees that flower and fruit in just 2–3 years instead of 7+ years, with predictable varietal traits.
   •   Industry practice: Nursery catalogs and industry publications consistently list Ōgonkan as available only as grafted nursery stock (接木苗). For instance, one nursery’s online catalog labels its Ōgonkan saplings as “1-year grafted seedlings” and notes explicitly, “苗木は接木で増やします” – nursery trees are propagated by grafting. Another fruit-tree nursery explains that virtually all citrus for sale are grafted onto rootstocks, often delivered as budded or grafted one- or two-year-old trees . This is the de facto standard in the industry.
   •   Grafting techniques: In Japan, common grafting methods for citrus include whip grafting and budding (芽接ぎ) in spring. Some prefectural agricultural centers have published guides and even videos on proper citrus grafting techniques . Grafting is typically done in late spring (around April, when sap flow is active) to ensure good cambium contact and healing . The success rate is high when done properly, and once the scion bud takes, the young Ōgonkan tree will essentially behave like a mature tree branch on a young root system, blooming and setting fruit much sooner than a seedling.
   •   Summary: All evidence indicates grafting is the preferred and most widely used propagation method for Ōgonkan. This method guarantees genetic fidelity to the original variety and significantly reduces the time to fruiting . Japanese government and academic sources emphasize that grafting is almost indispensable for citrus cultivation at commercial scale.

Cuttings (挿し木)
   •   General feasibility: Propagating Ōgonkan by cuttings (rooting a piece of stem) is possible, but it is not commonly practiced. Citrus cuttings are known to be tricky – woody citrus cuttings often do not root easily under standard conditions. A gardening Q&A response on a Japanese site confirms this: “Lemon cuttings will root about half the time even if just stuck in soil and left alone, but other citrus hardly root at all – they usually just wither”. This reflects the experience that lemons are relatively easy to root, whereas mandarins (mikan) are much more difficult.
   •   Specific to Ōgonkan: Interestingly, one respondent on a Japanese forum speculated that “Ōgonkan has a high possibility of success” with cuttings. This anecdotal claim suggests that Ōgonkan might root better than Satsuma mandarins (温州みかん), perhaps due to varietal differences. However, this is not a formally documented result – it’s an opinion from an experienced grower, not a controlled study. So while a few growers have reported or hypothesized better rooting with Ōgonkan, it remains anecdotal evidence.
   •   Challenges and professional advice: A more detailed expert explanation (chiming in on another Q&A) provides insight into why cuttings are generally avoided for citrus in Japan. The expert notes that under controlled conditions (proper temperature, humidity, bottom heat, etc.), citrus cuttings can be made to root. However, the key reasons cuttings are not the norm are: (1) Rootstock advantages – using a strong rootstock via grafting helps dwarf the tree and induce early fruiting, which a cutting on its own roots would lack; and (2) Vigor control – a tree grown from a cutting will express the variety’s full vigor (which in many citrus can lead to a large, unwieldy tree that is slow to fruit). In short, “Yes, you can do cuttings… but normally one grafts onto rootstock”, because it’s much more practical.
   •   Success factors for cuttings: For those who do attempt citrus cuttings (often hobbyists or researchers), timing and technique are important. Some Japanese horticultural guides suggest that late spring (March–April) or late summer (August) are suitable times to take citrus cuttings when conditions are warm and humid enough to encourage rooting. Using rooting hormone (発根剤) and maintaining high humidity (for example, by covering the cutting or using mist) can improve success . Even so, the expected rooting period can be several weeks to months, and success rates are variable. There is little specific published data on Ōgonkan cutting success rates, so this remains a marginal propagation method.
   •   Bottom line: Cuttings are not a standard propagation method for Ōgonkan in Japan, though they are biologically possible. Commercial nurseries do not propagate this way because grafting is more efficient. Cuttings might be used on a small scale by enthusiasts or for experimental purposes, but Japanese industry literature overwhelmingly favors grafting over cuttings for citrus.

Other Vegetative Methods (Layering, Tissue Culture)
   •   Air layering (取り木): Another vegetative technique is air layering, where a branch is induced to form roots while still attached to the mother tree, and then severed to become a new plant. In general, air layering is considered difficult for citrus, but it can be done with careful technique. A Q&A on a Japanese site details a gardener’s attempt to air-layer a mikan branch: after a few months it had formed a mass of callus but no roots, indicating partial success . The expert advice was to peel a wider ring of bark and use sphagnum moss without disturbance, to encourage root formation . This suggests that with proper method (ring-barking the branch, applying rooting hormone, keeping the moss moist), citrus branches can be induced to root. The Tokyo Metropolitan Agriculture center has even published a video demonstrating citrus air layering techniques . However, similar to cuttings, air layering is rarely used in commercial propagation of Ōgonkan. It’s more labor-intensive and not guaranteed to succeed, so it remains a niche method for specialty propagation or salvaging branches.
   •   Tissue culture and micrografting: In academic contexts, plant tissue culture has been explored for many crops, including citrus, to produce virus-free clones or mass-produce rootstock seedlings. In Japan, citrus micropropagation is not widely reported in public sources for this specific variety, but research stations have used in-vitro techniques and nucellar embryo culture for breeding disease-free lines. One example is the use of micro-grafting (grafting a tiny bud onto a seedling in vitro) to eliminate pathogens while propagating citrus clones – a technique used by some Japanese citrus research labs (though specific published reports on Ōgonkan were not found in this review). For the scope of practical propagation, tissue culture remains a scientific tool rather than a routine method.
   •   Budding: It’s worth noting that “grafting” in nursery practice often means bud grafting (芽接ぎ) – this is essentially the same outcome (joining Ōgonkan wood to rootstock) but done by inserting a single bud rather than a scion stick. Japanese nurseries frequently bud-graft citrus in summer, then grow the plant for a year. Budding is encompassed under grafting methods and is the technique by which most Ōgonkan trees are produced.

Conclusion

Japanese sources unanimously highlight grafting as the primary propagation method for Ōgonkan, due to its efficiency and reliability. Government agricultural extensions explicitly advise using grafting for citrus and caution against seed propagation except for breeding . Industry publications (nurseries and growers) reinforce that all commercial Ōgonkan saplings are grafted. Academic knowledge of citrus physiology (e.g. polyembryonic seeds) explains why seedling populations are avoided in cultivation despite the interesting trait of nucellar embryony that can produce clones. Cuttings and air layering are acknowledged but infrequently used – they are possible routes that some enthusiasts may try, yet they play a negligible role in mainstream Ōgonkan production due to lower success and agronomic drawbacks.

In summary, Ōgonkan is propagated almost exclusively by grafting in Japan, with seeds used only in special cases (such as breeding programs) and vegetative methods like cuttings or layering remaining experimental. This ensures that orchards of Ōgonkan maintain true-to-type fruit quality and bear fruit as early as possible, following the long-established practices in Japanese citrus cultivation .

Sources:
   •   愛媛県庁 かんきつ類Q＆A (栽培編) – Explanation of citrus propagation via grafting vs. seed  .
   •   花ひろばオンライン苗木部 – Ōgonkan product page (nursery stock description).
   •   富久寿園 柑橘辞典 – Ōgonkan entry (notes on Shōnan Gold nucellar seedling).
   •   Yahoo知恵袋 (Japan) – Citrus propagation questions (expert answers on cuttings and layering) .
   •   果物ナビ – General information on Ōgonkan fruit characteristics (for context on seeds).

Is there a nursery in the SoCal area that sells this variety?

Congrats!  How's it taste?
The premier chocolate refiner (a tricked out wet grinder) isn't too pricey.  I've had mine for ~10 years, it's a lot of fun to whip out a couple times a year and makes for some seriously amazing silky textures, but omg what a pain to clean.

Thank you! It's decent, texture is weird but tastes like chocolate!

Successfully achieved some level of fermentation using the contents of a single pod. Attached a photo of one of the seeds cut open. When I did this same 'cut test' a few days ago, the seeds were sort of grey with a ring of vibrant purple on the inside. Now they are closer to a deep brown.

Deep brown is what you want. They seem like they're not *quite* there yet (still a little bit of a purple tint), so I *could* ferment them more, but I don't want to risk over fermentation, especially because I've never done this before and don't want to ruin it. If the final chocolate flavor is a bit weaker than what it could be that's fine.

I looked up the temperature the beans tend to reach during fermentation, set a sous vide bath to a temperature within that range (116 F), then put a glass fermentation jar in the sous vide bath (with the seeds in the jar). Shook it every couple days, drained excess liquid, and looked for any signs of mold etc. I had the sous vide running and the water heated the entire fermentation (a week and a few days). Some aluminum foil did a great job of controlling evaporation from the sous vide bath.

Roasting now in the oven (300 F for 90 minutes) then will peel off the outer coating and grind the nibs. I know there are limits to how well you can do that without specialized equipment but I'm okay with it being grainy.

Very much enjoying the process, and the other members of the household are also finding it interesting. Will also be a fun thing to mention that I did in future conversations.

I agree that it's definitely more of a novelty. So many of us only know chocolate as a finished product from the supermarket; it's cool to actually go through the steps of making it. That said it's not at all practical.

People in temperate climates have successfully gotten them to flowering size, but basically by growing it indoors as a giant houseplant. You would also likely need two of them to get fruit. They're typically self-incompatible.

I think the fruit is fun to buy as a novelty, to try it and taste the pulp. If you leave the pulp on, you can ferment the seeds and actually make chocolate. The end result will be a bit grittier than what you're used to (you need specialized equipment to sufficiently grind the cacao nibs), but if otherwise done correctly you can still create something that is obviously and identifiably chocolate.

I bought those seeds 4 yrs ago. It fruited last year.
They did get that dark color for me. They were small, soft and sweet like strawberry guavas.
For some reason i can't attach the image, low memory message.

I'm planning to grow a number of them out, then cull once they fruit

During 22+ years of growing and studying both varieties, we found that if you grow it for fruit then Monstera deliciosa is the one to grow. Keep in mind even with the right variety, you have to harvest a fully mature fruit and have it ripened correctly for best quality fruit.

 Many people confused between 2 varieties of Monstera borsigiana /Monstera var. borsigiana  Vs Monstera deliciosa due to how they look somewhat similar to each other when they are young plants. There are some people call them large form and small form because word of mouth. Not many of them actually take time to grow these two varieties side by side for examination. They believe the term   " large form and small form" meaning Monstera borsigiana /Monstera var. borsigiana  and   Monstera deliciosa are the same species and the same variety.

"Albo" just mean white. It is not a plant name.  Albo variegata is the term that they use to describe a plant with white/creamy white variegated.  It applies to both varieties, Monstera borsigiana /Monstera var. borsigiana  and   Monstera deliciosa.

Monstera borsigiana albo variegata   https://www.youtube.com/watch?v=yucIGIkITA8

Monstera deliciosa albo variegata (seed grown) Monstera northern lights   https://www.youtube.com/shorts/bcLCTcX-VHg

This video has more examples of Monstera albo variegata including Monstera deliciosa albo variegata 'Thai Constellation'   https://www.youtube.com/watch?v=sBprGjzCSGg
 
Many Monstera deliciosa albo variegata 'Thai Constellation' in the market today were from TC. It needs more time to adjust to outside of the lab, than the one was propagated from cutting of a plant already grown many years in natural environment.

My advice is collecting the right ID plant and hands on growing it for years to learn about them.

The plants known as 'large form' 'deliciosa' etc and 'small form' 'borsigiana' etc are taxonomically the same species, Monstera deliciosa. They just represent variation within the species. It's similar to how a chihuahua and a rottweiler are the same species (Canis familiaris, the domestic dog). We understand they are the same species, but we also understand that if you feed a chihuahua really well, it will never become a rottweiler. In the aroid collector community, the debate about this could analogized to one person saying 'chihuahuas and rottweilers are different' and another person replying 'no they're not, they're the same species,' when in fact both are true (they are different and they are the same species).

Sometimes the 'they're the same species' people will bring up the fact that 'borsigiana' is a synonym of deliciosa, but again, back to the chihuahua vs doberman example, being the same species ≠ being the same. Additionally, synonyms in botany have a particular meaning. They can be homotypic or heterotypic. To my understanding, borsigiana is a heterotypic synonym of deliciosa.

From Wikipedia:

Heterotypic, or taxonomic, synonyms (sometimes indicated by =) have different types. Some botanists split the common dandelion into many, quite restricted species. The name of each such species has its own type. When the common dandelion is regarded as including all those small species, the names of all those species are heterotypic synonyms of Taraxacum officinale F.H.Wigg. Reducing a taxon to a heterotypic synonym is termed "to sink in synonymy" or "as synonym".

There *is* a distinct species that looks visually similar to 'borsigiana' called Monstera tacanaenis that was recently described. One of the identifying characteristics is that the seeds pop out of the fruit on their own.

The seeds of M. tacanaensis are extruded from the fruit at maturity, a phenomenon first reported here for the genus.

https://www.researchgate.net/publication/344377658_A_comparison_of_Monstera_deliciosa_and_M_tacanaensis_with_comments_on_Monstera_section_Tornelia_Araceae

I don't know what 'taurii' is exactly (it seems to be of horticultural origin) but would assume it's also some form of deliciosa. I have it growing and so far it seems like it's almost an intermediate form between 'small form' and 'large form' so maybe whoever originally made the plant crossed them together.

Question for you. I have never tasted a Cacao, what does it taste similar to, is it worth buying it to try it for the first time?

it's interesting, similar to mangosteen but not much pulp on the seeds. you can tell it's ripe because if you shake it gently you can feel and hear the inside of the pod rattling around. the seeds smell like chocolate, and taste somewhat like chocolate but extremely bitter. there is a special process to ferment them that lowers the bitterness at which point you can process it into cocoa powder and cocoa butter. to me the appeal of buying the cacao pod is to try the fruit, try one of the seeds raw (to notice the chocolate taste as well as the intense bitterness removed by processing), then try to grow one of the seeds into a houseplant.

20137 Pioneer Blvd
Lakewood, CA 90715

I don’t like propagating guavas, but when I used to grow professionally for a couple large nurseries here in CFL, I had pretty good success at rooting cuttings. Just a ballpark but figuring I have rooted at least 50k guavas from cuttings. They aren’t easy, but I know the tricks for getting higher percentages.

I'm sure a lot of us would be really grateful if you could share what you know about this.

Someone in my neighborhood has this growing in their yard. I know almost nothing about Annonaceae and am not sure what the tree is. Didn't want to bother them to ask (would've had to knock on their door etc)

It's a small tree maybe 6 feet tall. I think there's two of them right next to each other

Encountered a strange problem from my China(carmine) guava since 2 years ago. It disturbing that the tree is no longer producing fruits with the pinkish skin, the skin is green, shape is round like typical varieties and no sweetness and bland. Seriously i dunno what happen.It was fine for the first 10 years and suddenly it's like the variety has just changed by itself. If anything is the culprit, it could well be the weather i think. i am in the ultra tropics. Weather pattern has change a bit though not much, dry spell are much hotter and rainy seasons are more intense. but how that would affect the varietyi am still puzzled.  Anyone has experience encounter similar thing?


Jet

If it's grafted maybe the rootstock has put out branches