In the islands around Amami Oshima, just north of Okinawa, Japan, there exists an odd type of Cycas revoluta known in the west as variety aurea. This is not your typical king sago, nor is it the result of poor growing conditions, bizarre horticultural techniques, or a virus. It rather is a consequence of a genetic anomaly, as we’ll see in the following picture sequence.
Cycas revoluta v. aurea is a naturally occurring form that boasts an interesting color pattern on its otherwise normal fronds – each pinna is tipped in gold. These yellow tips are attractive to some while others think it makes the plant look diseased or ill treated. To my eye, the regular pattern of yellow against the dark green of the inner pinnae is indeed attractive, particularly at a distance. In Japan it goes by the names kogane sotetsu (gold cycad) and kinbuchi sotetsu (gold rim cycad). The following is the growth cycle of a plant over the past year here in southern Japan.
In June the plant begins its flush and by early July the new fronds have matured and hardened, but remain a bright green color. If you look closely, you can see that already the very tips of the pinnae are turning yellow.
By early August the yellowing process is in full swing and the inner segments of the pinnae are now fully mature and taking on the characteristic deep green of this species.
A couple weeks later the yellow has deepened further and the plant is at its best, with little or no browning of the tips yet.
In early September the tips begin to turn brown and the yellowing process continues down the pinna’s length. By mid October this yellowing stops and the fronds stabilize in this form.
The plant remains in this condition for the rest of the winter and spring until the new flush of fronds are produced. The peak beauty of the plant is from late August into early September before the browning process begins. In truth, it is pretty from a distance all winter long since you cannot discern the browning unless you take a closer look. Some plants seem to brown more slowly than others, so likely cultural conditions are at play as well. Next year I’ll try using fungicide to see if this slows the browning down (update, April, 2013: the past summer the plant grew its fronds a bit later and the yellowing process continued throughout the winter months and seems to have peaked right at the beginning of spring. I’ll leave the old fronds on into the summer and see what happens. Happily, there has been very little browning so far, so each year seems to yield a unique result).
The yellowing process is a result of weak tissue in the outermost part of the pinnae. This is not induced through overwatering, under watering, lack of nutrition, too much fertilizer, etc., as some have supposed. Normal plants grown right alongside this one continue on without any yellowing whatsoever. Pups taken off the main plant have produced the same pattern of yellowing, hence it must indeed be a genetic trait. To what extent this effect is passed on to its progeny, I cannot say, though a certain percentage of seedings of both varieties alba and variegata do grow true from seed.
Not a plant for everyone, but very popular in Japan, this odd form of Cycas revoluta remains a fairly rare cycad in cultivation outside its native homeland.
Here’s video showing the plant from its recently flushed state in late July 2012 thru April 2013.
7 Replies to “Cycas revoluta v. aurea, an odd type of king sago”
anychance you might know where some of these might be purchased????? Thanks
Hi Steve. I know that true Cycas revoluta v. aurea are grown in quantity in Australia, South Africa, and to a lesser extent, Europe. There are plants in the USA as well, but true ones are rare as hen’s teeth. It is said that plants in ill health have been sold as v. aurea to unsuspecting folks. The only nursery I know of currently stocking them is Jurassic Garden in North Hollywood, CA. The price of just one small offset might cool your engines though.
As for seed, you’ll see them from time to time for sale. I cannot comment on if they come true from seed. I do know that v. variegata and v. alba both are produced by seed, but the results are variable and uncertain, and even here in Japan such seed is expensive. Locally, I have never seen any variegated Cycas revoluta for sale, so all my plants have been bought online from growers from the southern islands – Amami Oshima and Okinawa – where these plants come from. Outside of Japan I would not trust people selling seed of these plants however.
Sorry I couldn’t be of more help.
I have a sago that is about 25 years old now and it has always developed yellow tips like these. I thought for years that it was lacking something, but it seemed healthy and fine. As the branch ages the yellow continues down and the tips are light and darker brown in thin bands, It gives the fronds a shimmering effect that I think is beautiful. I have removed some of the “pups” from the trunk and have 10 planted, 7 that are almost 2 years and 3 that I just did last Spring. Since they are clones I would think they would all be alike but when they first got fronds some of them had more yellow at the tips than others, looking forward to see how they develop. I live in the Central valley of California about 30 miles south of Redding.
I should have said I have a Cycas revoluta. It was purchased as a small, cheap plant from a store, just lucky I guess that it is different than the standard plant. The yellow at the tips is not as wide as some like the example photo above. Also, some of the pups from the trunk had more yellow than the parent plant, but right now they are all green, curious as to why they seem to have changed. They are still small with fronds about 6-8 inches long or so. I am hoping they get a new set of fronds this year and that the three new ones start to sprout.
Yes, it sounds like you lucked into finding a plant of variety aurea. I too have separated off a number of pups from the main plant and there has been some variation in their leaves as well. I am under the impression that the exact pattern of yellowing varies based on the state of the frond’s tissues. I cannot say exactly how, but the amount of sunlight as well as the moisture content of the fronds themselves may make a difference in how they show the yellowing feature. No doubt the general health of the frond makes a difference as well. The dying tissue eventually browns starting at the tip of each pinnae, so the trick is to slow that process down. I’m considering applying fungicide over the next growing season in an attempt to slow down this process. I have no idea if this will help.
I have only grown my plant for one season now and I’m very interested to see how it develops next year. Of course I’ll post any differences I see over the coming seasons.
Hi I am considering purchasing 150 of these seeds
are the yellow fronds just a mutation (one in a million) or can I expect all 150 seeds to have the yellow fronds
I can’t comment on that since I haven’t grown this one from seed. I have grown the yellow flushing form (v. alba) from seed and even with those, they don’t all come up true. Of course the quality of the seed you start with is critical. I have seen seeds of v. aurea for sale here, but haven’t tried them – I have to admit I didn’t trust the seller though. The seeds were too cheap and v. alba seeds I bought from that seller didn’t come true at all.
Regardless, I wouldn’t expect to get 100% v. aurea seedlings.