Nannorrhops, The Enigmatic Palm

by Robert Lackner, Burggasse 1a, 2405 Bad Deutschaltenburg, Austria
Chamaerops No. 45, published online 29-01-2003

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From left to right:
- A massive "green" Nannorrhops at Fairchild Tropical Garden, Miami. Photo: Gibbons/Spanner.
- Some like it hot: a "green" Nannorrhops ritchiana in the desert in the mountains north of Sibi, Pakistan. Photo: Gibbons/Spanner.
- Green Pakistan form. This plant has withstood -9°C outside in the pot during the last winter without problems.
- Silver Pakistan form, green Pakistan form, silver Iran form with intense silver fans, silver Iran form with green-blue-yellish fans.
- Costapalmate fans of the silver Pakistan form.
- Palmate fans of the green Pakistan form.
- Trunk with ornage fur, green Pakistan form.
Photos: Robert Lackner

When your interest in palms was awakened it was almost certainly caused by one of the many Trachys, by a Phoenix, or Washingtonia, all of which can be seen frequently in milder and sometimes even cooler parts of Europe. Then you learn and read more about several other species, some of which can also be grown under really harsh conditions, be it frost, drought, or heat. After a while you'll find a really good palm book and when flying over the pages you'll almost certainly make a pause at the page of Nannorrhops ritchiana, the Mazari Palm or, as it should be called, the Enigmatic Palm. You want to know why this palm is a mystery in my eyes? Well there are many good reasons:

Enigma No. 1

This palm is so common and abundant in its habitat and yet so few plants can be found in cultivation. On one hand everybody talks about it, but on the other hand only a few people grow these palms successfully.

Enigma No. 2

Also adding to its mystery are the areas where this palm grows. The deserts of Afghanistan, Pakistan and Iran are not on most people's lists for their family holidays, and even if they were, the current situation makes it even more difficult to visit these places than it was a year or so ago. Thus, only a few palm enthusiasts have seen this palm in habitat. This, in my opinion, has allowed many rumors about its climatic growing conditions to arise, especially in the beginning. I possess four palm books where this mysterious palm (which is named after its original collector David Ritchie) is mentioned. Three of these books claim that these plants may be covered with snow for long periods during the winter. One book even mentions that it is covered with snow for months at a time. Climatic data on these areas indeed suggest that it can become really cold in some places where Nannorrhops grows, as far as the absolute extreme minimum temperature is concerned. This, however, only applies to some of Nannorrhops' habitats, not to all of them. The climatic data also show that these areas have a fairly high mean annual temperature and almost no precipitation. This suggests that the plants are normally not covered with snow for weeks or months because it rarely snows there, and if it does, the snow certainly melts soon in the warm desert sun of these southern regions. This brings us to the next enigma, and the question of how hardy this palm really is.

Enigma No. 3

All of the above mentioned palm books state that this is an "extremely cold-tolerant palm", which is a relative term, because you don't know from which (geographical) point of view this was written. Two books are even more precise, suggesting it can tolerate temperatures as low as -20°C or even -26°C. This is certainly a point which almost forces the inexperienced palm enthusiast to purchase this palm at any price, because in his day dreams he already sees a nice palm with its fan leaves swaying outside in a gentle arctic breeze at -25°C. I, too, thought "I must have this one" some eight or nine years ago when I first ran across the Mazari Palm’s description. In addition, many plant nurseries offer this as a palm that is hardy in many parts of central Europe. But is this really the case? Fact is, that hardly any Nannies are growing successfully outside in central Europe and you can read more about failures than about successes. Even in relatively mild areas, such as southern England, this hardy palm does not seem to grow satisfactorily. So what is true and what is not?

As for most exotic plants, this question does not have a straight answer. Nannorrhops ritchiana is indeed a very frost-tolerant palm in habitat, but the frosts there are very dry and, compared with central and western Europe, short lived. Many parts of Central and Western Europe, however, are rather moist and humid, especially during the critical winter months. This, in my opinion, makes this palm unsuitable for outdoor cultivation in many areas, unless you can create a good shelter to keep the plant completely dry while also allowing it to get enough light, as this palm requires bright conditions even during the winter. Furthermore, Nannorrhops requires very good drainage. It is odd that in England so many rather tender (which again is a relative term) palms can be grown without shelter (e.g. Phoenix, Arenga engleri), but the allegedly extremely frost-hardy Nannorrhops simply rots away and dies, unless of course it has either a very favourable and/or dry place.

In light of all this, I strongly disagree with nurseries selling this palm as being hardy in almost all parts of central and western Europe. If this palm can be grown in the cooler parts of Europe, then in my opinion more continental areas with cold, dry winters and hot summers have the best theoretical chances for outdoor cultivation, unless their winters are too cold for this palm to grow. That means that without special preparations this is not the ideal palm for countries that have mild but moist winters (e.g. England, the Netherlands, Belgium, the northwest of France and the northern parts of Germany). This palm would probably be better suited to Hungary, Slovenia, Croatia, Slovakia and maybe eastern Austria. But even in these parts a rain-sheltered place, good drainage andÑduring severe coldÑsome frost protection is certainly necessary. (I need not mention that Nannorrhops has no problems growing in southern Europe, and therefore I hope you don't mind if I focus on the less favourable regions of Europe).

Regarding Nannorrhops' frost hardiness you should take into consideration that Washingtonia filifera is, in the Southwest of the States, regarded as being hardier than Trachycarpus. The reason is clear: Trachys are certainly not suited to desert climates and thus won't grow very well there. W. filifera, however, is really exceedingly hardy in such dry climates and can therefore indeed cope with -20°C for short periods. W. filifera is cultivated in areas (e.g. El Paso, Texas or St. George, Utah) where -20°C can be reached (although it does so very rarely), and where frosts down to -10°C are fairly common. But the frosts there are dry and short lived, which makes a huge difference. In central and western Europe, on the other hand, W. filifera (if you have the true type; many Washingtonias being offered as W. filifera are actually W. robusta) is rather difficult, because it needs fresh air and resents moisture, especially during the winter, and is therefore sometimes damaged at temperatures around -5ÁC. Again, the lower the humidity, the more cold it tolerates. W. robusta, although in habitat not nearly as frost tolerant as W. filifera, copes much better with moisture and is therefore better suited to our gardens and greenhouses. So you see, if a palm can cope with -20ÁC in a certain climate, this must not lead to the conclusion that it can be planted out in central Europe.

There's one thing my experience with Nannorrhops shows clearly: It is certainly better suited to our winters than Washingtonia filifera and thus it is certainly hardier. During the winter 95/96 I wintered a blue and a green Nanny seedling outside just with a plastic pot placed over it for rain protection. That winter was the longest and wettest winter I can recall (see my article in Chamaerops No. 30) with an absolute minimum of -19°C. The green Nanny seedling just survived the winter and began to recover later, but very slowly. The blue Nannorrhops died. Formerly I was too inexperienced and thus too impatient and wanted to plant them out as soon as possible. Now I know that it makes no sense to plant out seedlings of any palm, let alone of a palm that needs much heat to achieve a good growth rate. I therefore dug up the surviving green Nanny and placed it in a pot again.

Enigma No. 4

As I mentioned before, there are Nannies with different leaf colours, which leads me to the next mystery: different species. It is still unclear if all the different forms of Nannorrhops can be lumped together into just one species. Formerly four species of Nannorrhops were recognized: N. ritchiana, N. stocksiana, N. arabica and N. naudiniana. H. Moore lumped them into just one variable species, namely Nannorrhops ritchiana. Now, doubts from experts arise, suggesting that some of the different forms found in habitat may indeed be separate species.

I can attest that the three forms I have look quite different from one another. I have the green form from Pakistan, the blue Pakistan form (also offered as 'Silver form'), and a silver form from Iran (sometimes referred to as N. arabica or N. sp. 'Iran'). It seems that the Pakistan silver form is by far the least hardy, which was also my experience, whereas the Pakistan green form and the Iran silver form seem to be hardier. The most obvious difference between the forms is their leaf colour, which ranges from an intense silver-white (Iran form), to a moderate silver-blue (silver Pakistan form), to plain green with bluish undersides (green Pakistan form). The varying amount of insect pests these plants attract also suggests there are differences between the forms. The green form is obviously the least tasty as I have hardly ever seen any insect pests on its leaves. The Iran form suffers only slightly, whereas the Pakistan silver form is sometimes moderately attacked by pests. The leaf bases of my three forms are also different. The green form is partly covered with an orange fur that can be seen easily. The Iran form shows only a very light orange-brown fur, whereas the Pakistan silver form completely lacks this characteristic. Another distinguishing characteristic is the leaf form. The silver forms from Iran and Pakistan have costapalmate leaves, whereas the green Nanny has palmate ones. Taking all of this into consideration, one can see that my experience supports the theory that not all of the former Nannorrhops species should have been lumped together into just one, but of course more scientific proof and detailed examinations are neededÑsuch as examining the flowering characteristics of these palmsÑbefore any solid conclusions can be made. Unfortunately, the necessary plant materials appear to be hard to come by, so it'll still be a while before we palm enthusiasts are better informed about Nannorrhops' scientific status.

As you can see, 'Enigmatic Palm' is really an appropriate title for Nannorrhops. It is certainlyÑespecially in the cooler regions of the worldÑone of the most talked about palms, and despite that, so little is known about it. And what's more, some of the information given is simply wrong. This has led to the creation of legendary myths about the palm from the deserts of Afghanistan, Pakistan, and Iran. Hopefully these myths will give way to more reliable and scientific information that will certainly save the lives of many Nannies that would otherwise just rot away or barely grow in many of the colder regions of Europe.

Reading this article you might suppose that I want to convince you to leave Nannorrhops to the experts or for warmer climates. No, definitely not! I encourage you, in fact, to buy one or raise one from seed, but give it the growing conditions it needs. I have been experimenting with Nannorrhops for seven or eight years and I can assure you it's really a marvelous palm.

Enigma No. 5

Another myth about Nannorrhops is that it is a slow-growing palm. It is just slow growing when given the wrong conditions! If you know how to raise them, however, you can have a splendid looking palm within only a few years. I purchased my green (Pakistan) Nanny as a 30 cm (1 ft.) seedling, still with seedling leaves. Now, not even six years later, I have a wonderful double trunked palm with a height of almost 150 cm (5 ft.) without the pot. The trunk diameter at the base of the taller stem is already 12-13 cm and it is still growing fast. Even much faster growing is my silver form from Iran. I raised it from seed three and a half years ago. Now it measures 100 cm in height!! Doesn't really sound like a slow growing palm, does it?

So what is the proper way to raise them?
• Use large pots.
• Keep them very hot (30 - 45°C).
• Keep them very moist during the hottest temperatures.
• Use (plastic) saucers during this time, so that the plants can stand in water.
• Allow them to soak up the water from the saucers before refilling them.
• Reduce the watering as it becomes cooler. The lower the temperature, the less water they need.
• Keep them very dry in winter if they are in an unheated greenhouse. If you keep Nannorrhops in a heated greenhouse do continue watering, but not as excessively as during the hot summer months.

Germination

I germinate Nannorrhops seed like any other palm, in a transparent plastic bag, but with two little differences: 1) I keep the seeds at temperatures between 30 and 45°C as these hot temperatures are necessary for good results; and 2) I take the seedlings out at an earlier stage than I would for Trachycarpus, for example. When germinating Trachycarpus it does not make a big difference if you leave the plants somewhat longer inside the plastic bag. Nannorrhops, however, seems to bring slightly better results if you take them out and pot them up a little bit earlier, because of their strong root growth. I usually take them out when the first seedling leaf has just begun to appear. Then I plant it in a deep plastic pot to allow the first roots to grow unhindered for a while. Leaving the plantlets inside the plastic bag longer means that the roots of the seedlings get mixed up and the necessary separation of the plants afterwards causes some stress. Therefore it's better to pot them up while the roots are still small.

The first seedlings usually appear after three to six weeks. As far as the silver forms are concerned most of the seeds germinate within two months. I achieved a germination rate of 85 to 90% with both silver forms. The green form seems to germinate over a longer period. Some seeds can take over a year to sprout, some only a few weeks after sowing. But generally they also germinate satisfactorily.

Soil

I do not use any special type of soil. Nannorrhops seems to grow equally well in regular garden mold or soil for pot plants. To my surprise, however, they did grow much more slowly in sandy soil. While they grew nicely even in this sandy soil, the plants that had been growing in light soil types grew much faster. I also fertilize the Nannies like any other pot plant. As such, my treatment of Nannorrhops, Washingtonia, or Trachycarpus is the same, except that I keep them at different temperatures during the growing season.

Conclusion

All of the different types of Nannorrhops are wonderful plants. They are exceptionally good palms for the heated and unheated greenhouse and almost trouble free. The green form especially is completely trouble free, as I have never, ever had any problems with pests and diseases, despite the fact that this plant was, until last month, in the greenhouse year round. During the first three years I kept it in an unheated greenhouse and afterwards it remained two years inside a heated one, where it grew side-by-side with a superb coconut palm. Would you believe that these two palms thrive under identical conditions? The Iran silver form is a must because of its beautiful colour, and it is nearly as trouble free as the green Pakistan form, in heated greenhouses as well as in unheated ones. The Pakistan silver form is probably the most 'tender' of my Nannies. If you keep it permanently in a greenhouse you'll surely fight sometimes against some insect pests, but that has never been a big problem. It is also an interesting palm because of its beautifully coloured leaves.

During the last summer the green Nanny became too broad to be kept in my rather small greenhouse, so I decided that IÔd plant it out next year. Since then I have been keeping it outside in the pot, so that it gets used to the colder temperatures outside. I'll leave it outside as long as temperatures do not fall below -8 or -9°C, and then winter it in a cool place. Next spring I'll plant it out in the hottest and driest position I have in my garden. I feel it has a good chance in our climate in this favourable spot, as it would be completely rain sheltered and would see sun from dawn till dusk. Our hot continental summers will do the rest and our normally very dry winters will hopefully be dry enough.

During the last four winters we didn't see much snow here and temperatures never fell below -10°C. The summers were very long, hot, and very dry, which caused tremendous havoc agriculturally. To such conditions Nannorrhops would be ideally suited. However, I have no illusions that some really cold winters will come; it's just a matter of time. When it does become really cold (-20°C) again some winter (which happens about every 15 years or so), I'll be prepared to help the green Nanny through the worst of the cold.

If the green Nannorrhops grows satisfactorily during the next two or three years, then the silver Iran form will be the next to be planted out, as it'll be quite large then. According to their habitat, these two Nanny forms are hardy enough to tolerate temperatures of -20°C in dry conditions. I'll see how they cope with the not-so-cold but rather foggy periods here, which can also occur during the winter. This is probably the only drawback of our climate as far as Nannorrhops' needs are concerned. Newer palm literature suggests, and my experience shows, that the silver Pakistan form is certainly the least hardy in terms of low temperatures. So this palm is, in my opinion, not suitable for outdoor cultivation in my area.

If you want to see some nice, mature Nannorrhops, you can find them at the Rome Botanic Gardens. Probably the best known, this green Nanny has a huge winding trunk. The most beautiful Nannies I have seen grow in the garden of Villa Thuret in Cap d'Antibes in the South of France. There you can admire a beautiful double trunked and upright green Nanny about 3 m in height, and, beside it, a somewhat smaller plant. I also saw plants in Huntington Garden in California, and I've heard of large plants in the Fairchild Botanical Garden in Florida and of one in a private garden in Florence.

The bottom line is that, if you can offer Nannorrhops the appropriate conditions, you should get one as soon as possible. You wont regret it! Although Nannorrhops will still remain somewhat of a mystery until experts do further examinations, I hope that I have given you a brief insight into this wonderful palm that might help you to grow them successfully. I'm not an expert as far as the classification of palms into their species is concerned, and therefore I don't know whether my observations of the characteristics of the different forms are useful or not, but I'm eager to know what will happen with the Enigmatic Palm in the future.

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