Pseudocydonia sinensis

Chinese flowering quince, known as Karin in Japan, is a species of fruit tree native to China.   The species is known for pink flowers in late Spring, exfoliating bark, and red to yellow fall color.  In this post, I’ll walk you through a few techniques for creation and maintenance of this species and show off a Karin that will debut at the Kokufu-ten for the first time next February (2013).

In the world of bonsai, there are a few varieties of Pseudocydonia sinensis so before creating or buying one for that matter, you should know what you are getting into.  For shohin and kifu (smaller) bonsai, seedlings known in Japan as “Misho Karin” or “Jikarin” are best.    A selection of an especially good seedling that is asexually propagated (cuttings or grafting) is called “Himekarin”.  In the Japanese bonsai community, the lineage does not seem as important as the characteristic that makes the selection desirable. I’ve asked four different professionals what the name of a rough barked pine was at an exhibition and received three different answers.  This is frustrating for a plant nerd like me.  There is a new “hime karin”, or small karin selection nick-named “Isai”; a term for any species of plant  which shows strong flowering precocity (flowers even when very young) and has naturally thin twigs.   We will get back to why this is so cool later.  The more common type seen in bonsai is “Jikarin”.  This variety has larger leaves, thicker, branches, and flowers/fruits reliably.  We’ll start with seedlings.

To grow Pseudocydonia from seed, collect from ripe fruit or purchase from a reputable seed supplier who can tell you how old the seed are and the provenance (where the seed were collected); this goes for any seed purchases.  Provenance is important especially for bonsai as seed collected from trees in a colder climate or lower USDA Climate Zone number will likely be more cold hardy.  Put all seed in a cup of warm water and do a “float test”.  Seeds that float generally do not have a viable embryo and should be pitched.  Cold stratify seed for 3 months or sow in Fall and protect from rodents; I like to use chicken wire to cover the flats.


Seedling quince have smaller leaves, more delicate twigs, and do not develop thick trunks quickly.  This variety does not flower easily; it may take decades and even then be sporadic.  It is a compromise to lack the reliable flowers and fruit, but be able to have the exfoliating bark and not have to deal with the excessive vigor found in Jikarin. Maintenance work is generally limited to removing leaves at the base of stems with no latent buds below, shortening vigorous new shoots, and sometimes cutting the largest leaves shading branches below in half or removing completely.  Wiring is best done during May (in Osaka) after defoliation.  Physiologically, this would be some time just after the new leaves fully harden off.  Wiring any type of Pseudocydonia in late winter before or just after the leaves pop is a bad idea.  The branches are stiff and will snap easily.  This is however, a good time to prune thick terminal shoots or remove large branches.

For Chuhin and Ogata (larger) bonsai, the commonly available Karin that has large leaves, a fast growth rate, and large fruit will work well.  These are referred to as “Tokarin” and are usually grafted.  Tokarin are notorious for producing thick shoots quickly leading to an inability to bend in the future.  It’s best to wire for form at an early age.  I would recommend defoliating, wiring the long shoots with aluminum, then placing the branches before shortening to a desired length with wire snips.  Cutting then wiring a short shoot will likely lead to pinching the shoot and die-back.  Small cuts heal very fast.  Big cuts will heal in time, but perhaps not in a time-frame you might like.  Maintenance is a little more labor intensive and will be covered below.

The previously mentioned “Isai Himekarin” is the best of both worlds.  You can have the soft, thin branching but also get a reliable round of flowering even on a young tree.  You don’t get the explosive growth of Jikarin, but with patience, a chuhin covered in 100ish fruit doesn’t seem out of the question.  Here’s the best part; the fruit are the size of golf balls!  There is an old Japanese grower somewhere patting himself on the back and smiling large right now : ).

As with any species of plant, knowing where it is from and what it’s related to can tell you a lot.  Psedocydonia sinensis is in the Rosaceae Family, so it is succeptable to pretty much everything bad that attacks plants including fire blight (Erwinia amylovora).  This also means you can’t import them to America. The EU still allows them and I’d bet 100 Australian Dollars they aren’t allowed Down Under.   Karin however, is more resistant to infection than other species like Cydonia oblonga (European Quince) and some species of Pyracantha and Cotoneaster.   Import bans on entire plant families is something I have an issue with, but I will stay off my soap box for now : ).  Karin are almost always the first tree to leaf out so they should be re-potted accordingly.  Being first in line for a re-pot  also means they should be giving whatever fertilizer regimine you use earlier than most; and don’t be stingy with it either. Moisture levels in the soil should never drop too low.  This species stays thirsty from leaf pop to leaf drop!  You can make the fruit shine and intensify the fragrance the fruit emits during and after ripening by polishing with a soft cloth.

This clump style Karin has been at Kouka-en for about 10 years and is one of my favorite trees here.  A client in Shikoku entrusted Fujikawa-san with the transition from a quality bonsai to a world-class, highly refined show tree.


So far this year, the tree had the thickest and most unsightly branches removed in January, the strongest shoots as the tree flushed shortened or removed depending on location, and the largest leaves in the silhouette were cut in half at the beginning of April.


Now, it’s time for defoliation.  Every leaf in the outer silhouette was removed.  Then any leaves inside that were shading shoots below or seemed too strong were removed or cut in half.  This leaf surface reduction technique (shown to the right) alone when done on most deciduous trees can be extremely helpful in letting light and air into the canopy.  The timing for thinning of any deciduous tree is extremely important.  This particular tree is being thinned “on time”.  However, in preparation for the Kokufu ten, this tree was allowed to retain more branching in the canopy during thinning to look better for judging.

 This comes at a price as you can see below.  Never underestimate the resilience of a Karin though!  I will be struggling to see into the canopy of this tree in a month or so.

Now that defoliation of the outer portions of the tree is complete.  The inner buds will gain strength.  If you follow my blog or take classes with me in the future, one point I will continue to hammer home is the importance of balancing vigor and increasing the strength of inner buds and branches.  These branches with leaves still attached will have a “head start” on the leaves soon to pop out.  The tree after defoliation  below.

After defoliation came shoot shortening.  Shoots were reduced to 2-4 internodes with priority placed on fullness and not on sustainability.  After the exhibition next Winter, the tree will be cut back agressively and the process of developing finely ramified branches will start over.



Now for the Final Product:

Thank you for reading this rather long post.  My next post will be on the matter of poodles and manicures…….