JARS v38n4 - The Satsuki Azaleas

The Satsuki Azaleas
Harold Greer, Eugene, OR

In the Azalea Series of the genus Rhododendron are many flower types and colors. One of the most varied and interesting groups are the Satsuki. Let's take a look at this group, but to do so it is necessary to lay some ground work to take away some of the confusion in the naming of these Japanese azaleas.
We often hear someone refer to an azalea or group of azaleas as an Indica or indicum . Someone else may call the same group of plants Macrantha and if you go to Japan you will see a common azalea that looks almost the same called 'Osakazuki'. Then someone will show you certain plants in a group of azaleas they call "Sat-su-key" that look the same. The next person you meet will call the same ones "Sat-skeys";. Then how about R. eriocarpum ? What does it have to do with these azaleas? Are you confused? If not, you are one of the few who isn't!
Let's try to examine this situation in more depth and see if we can make sense out of chaos. On the island of Honshu in the area of Tokyo grows a Rhododendron species known as R. indicum which was named by the botanist Sweet in 1833. This was later placed in the Azalea Series by the Balfourian classification or in the Subgenus Tsutsutsi by other classifications. Before Sweet named it R. indicum , a botanist by the name of Carolus Linnaeus named it Azalea indica in 1753, before it was realized that all azaleas were in fact rhododendrons. Why he named it indica which means "Indian" or "India", is unknown. Perhaps he had the mistaken belief that it came from the East Indies. Another thing that should be mentioned here is that this indica should not be confused with the tender Belgian or Southern Indicas which are of different ancestry.

How about the name 'Macrantha' we mentioned earlier? This was another name given R. indicum also in 1833 by the botanist von Bunge when he named it Azalea macrantha . This name has stuck and it is often used in the trade and you will see the many forms of R. indicum called by names like Macrantha Double, Macrantha Dwarf or just Macrantha.
In actuality R. indicum has had several other names such as R. decumbens , R. breynii , R. danielsianum , R. lateritium , R. hannoense , R. hagnoense , R. sieboldi and worst of all it was first published in Europe in Breyne's Prodromus in 1680 as "Chamaerhododendron exoticum, amplissimis floribus liliaceis".

In Japan R. indicum is known as "Satsuki-tsutsuji" since the Japanese in their own use do not use the Latin names. Those plants that belong to the Azalea Series are usually called tsutsuji (suit-suit-gee) and other rhododendrons are known as Shakunage (shock-u-nog-ay).
Now we come to the Satsuki azaleas and their relation to all of this. Earlier we mentioned two names 'Osakazuki' and R. eriocarpum . In Japan an azalea called 'Osakazuki' is planted by the thousands and in early June it seems to be in flower everywhere. It is seen in bonsai use frequently and it is not unusual to see a bonsai 'Osakazuki' that is said to be 300 years old. In the United States we do see this same plant under the name of 'Osakazuki', but it is also possible to find it under the name of 'Macrantha' which is probably because R. K. Beattie in 1929 introduced a Macrantha to the U.S. under the name of 'Osakazuki'. Since 'Macrantha' is equal to R. indicum , 'Osakazuki' is equal to R. indicum . 'Osakazuki' is listed in many books as a Satsuki and according to the "The International Rhododendron Register" there are two plants named 'Osakazuki'. One is the R. indicum we just discussed, the other is a Satsuki which is listed as "prize winner of Japanese Satsuki Society; single, large flowered, pink with touches of red." The 'Osakazuki' commonly seen in Japan and often pictured in Japanese books on Satsuki, however is the R. indicum , not the Satsuki.

It seems like we are going around in circles, so let's try to get back on track. Japanese authorities now feel that the origin of the Satsuki azaleas is a cross between 'Osakazuki' (equal to R. indicum ) and R. eriocarpum . Rhododendron eriocarpum is a species native to southern Japan which is similar to R. indicum , and some botanists have classified it as a variety of R. indicum . It is commonly known as the "Dwarf Indica Azalea" and in Japan it is known as "Maruba-satsuki". It generally grows south of the habitat of R. indicum . 'Gumpo' (also known as Gunpo) and it's clones are considered by some to be equal to R. eriocarpum , but others feel that they are crosses between R. indicum and eriocarpum and they are generally listed with the Satsuki group.
The Satsuki azaleas are the result of the crossing and back crossing of two very similar species ( R. indicum x R. eriocarpum ). These crosses done over many centuries, plus the addition of "sports" which this group is so prone to produce, have resulted in a great diversity of colors and flower types. It is possible other azaleas have been used in their parentage. Many theories on this exist, but still their main parentage is 'Osakazuki' x R. eriocarpum .

Now comes the question how should we pronounce the word 'Satsuki? Some in the United States will insist that it should be pronounced "Sat-skey". Others will insist that it be pronounced "Sat-su-key". Who is correct? It seems both are, as the Japanese themselves pronounce it both ways, depending on the area in Japan and the particular dialect used.
"Satsuki-tsutsuji" means fifth month azalea from the fact that it flowers in June, which is the fifth month in the year by the old Chinese calendar.

The Satsuki azaleas are low to medium growing depending upon the cultivar and the location in which they are planted. Most tend to flower in June, though time of flowering will vary with the area in which they are grown. They flower with or after the new growth appears, but the flowers are large enough that they are not hidden by the foliage. Many of the clones are unstable and will produce limbs of varying colors, and the theory is that in time any cutting taken from a particular clone will produce all the colors possible for that particular clone. The catch may however be in the phrase "in time," since it often takes much longer for all colors to appear on the same plant than seems reasonable. An example of the many colors that appear on one plant is shown in the picture of 'Gyokurei' which is illustrated with this article.

There is a great variation in flower type, size and color with the largest flowers being over six inches across. Other flower types include flowers that have no petals, only stamens which make a delightfully interesting appearance; fully double flowers; star shaped flowers; and in one type represented by the named clone 'Chojuho' the petals thicken and become leaf like lasting a full three months. One of the distinguishing features of an azalea is the fact that azalea flowers have five lobes. The Satsuki group is an exception to this rule however, as some clones have six and occasionally seven lobes, though flowers with five lobes can occur on the same plant. Of course any double type azalea may also have more than five lobes.

The leaves of this group are variable from types that have fairly broad leaves to types with narrow strap like leaves. A few have variegated leaves such as Shirafuji which is pictured. A superb clone for foliage is Kazan, a plant that is often sold in the U.S. as Rukizan. It has little glossy mouse-ear leaves which are most delightful.
All in all the Satsuki group is a very interesting and diverse group of plants which would make a worthy addition to any garden. To quote Hideo Suzuki (Vice President of the Japanese Rhododendron Society and our host on a recent tour of Japan) when discussing a Satsuki azalea fair we were going to see, said in his delightful Japanese English, "We rhododendron enthusiasts don't grow Satsuki azaleas; they are TOO beautiful!"