Seasonal Palm Growing
Nicolas Cock's experiences, trials, hopes and dreams
about growing hardy palms.
by Nicolas Cock, Essex, UK
Chamaerops No.38, Spring Edition 2000
Geonoma weberbaueri, at 2700m in Ecuador.
Palms in the winter
Its been almost 3 years now since I was bitten
by the bug and took the first step of purchasing my first
palm, a Dypsis Lutescens, which was summarily executed due to my
lack of experience. I have, however, bounced back since those dark
days and can now happily boast almost 100 palms in my collection,
of every conceivable shape and size. It was about a year before
I found out that there were mad men and women out there growing
palms in their gardens, even over the winter. I decided to investigate
further, which leads me to where I am today. I have developed the
obsession of leaving these poor defenceless plants to the mercy
of the weather and carefully recording exactly what effect our winter
climate has on them, sometimes with unexpected results.
To start with I was dubious about leaving any palms
in the gardengoing out and spending a few hundred pounds on
plants just to see them zapped into oblivion was not exactly my
idea of enjoyable gardeningbut once the palmophile comes out
in you, you begin to notice palms that have been growing in your
neighbourhood, right under your nose, many of them years old, and
so I thought to myself, why not? I live in Southend on sea (South
Essex riviera!!!) where I personally believe we have the best that
the weather has to offer, especially when it comes to palm growing.
Our yearly precipitation is the lowest in the UK, we have some of
the highest summer temperatures, and winter temperatures dont
drop too low. This past winter saw an absolute low of -4°C,
and we only had to suffer a few nights of below 0 temperatures.
Granted we dont get the full effect of the Gulf Stream that
the South West gets, but, no offence to its people, its too
wet there! I feel the River Thames helps keep temperatures a degree
or so higher, so Im in no rush to move.
Although still a beginner by a lot of
peoples accounts, Ive learned a tremendous amount over
the last couple of years. The question of cold hardiness in palms
is one of the subjects that fascinates me the most. The internet
and various magazines are crammed full of information regarding
hardiness and growing zones that our American cousins seem to covet
so much, but I think here in the UK and Europe we have to look at
things a different way. Technically where I live is situated in
Zone 9 (which means a minimum winter temperature of -1 to -6°C),
and being that -5°C is usually our absolute minimum, we feel
that we can firmly place ourselves in that zone. However, compare
that to another Zone 9 area such as Central and most of Southern
Florida, and it doesnt take an expert to work out that there
is no comparison when it comes to climate. Although Florida can
get several degrees of frost overnight, this is usually followed
by day temperatures of 15-20°C; in other words, back to the
conditions palms are used to growing in.
Here in the UK we have to put up with 3-4 months of
dull, cloudy days where the temperature rarely rises above 10°C
and night temperatures usually fall to a few degrees above freezing.
This leads me to believe that a palms hardiness should be
assessed by whether it can survive a British/European winter or
not, and not purely by the figure of a minimum temperature.
I have lost many small palms due, I believe, to the
lack of any real heat. I have a polytunnel where I try to prevent
temperatures dropping more than a couple of degrees below 0, and
a small greenhouse, where I keep my more tender palms frost free,
though even here losses have been high. Although it can be disheartening
to have these losses, I believe that I have learned a lot by experimenting
in this way. For instance, Ive learned that seed provenance
can play a big part when trying new species. I have tried out many
Copernicia seedlings this year, species including C. alba and C.
prunifera, many of which have succumbed to the low winter temperatures.
However, I managed to obtain seed of Copernica macroglossa from
the US from a parent that gets a regular frosting, sometimes as
low as -7°C!!! Needless to say, I havent lost a single
seedling (yet) and Ive allowed them to get frosted to -2°C.
Watering is another area that needs to be observed as well. I tend
to keep my palms very dry during the winter and water with a fungicide
solution about once a month just to keep any root rot in check;
its amazing how a little moisture and cold temperatures can
rot some palm roots in no time.
Other palms that have taken -2°C with little or
no damage include Wallichia disticha and densiflora, Wodyetia bifurcata,
Parajubaea cocoides, Dypsis decipiens, and Chamaedoria seifrizii
and C. oblongata. Happily the garden and unprotected old favourites
are doing well. Phoenix canariensis, Rhapis excelsa, Brahea armata,
Brahea edulis, Trithrinax acanthocoma, and Washingtonia robusta
and filifera have all come through our lowest night of -4°C
so far without being scathed, although Livistona chinensis suffered
slight tip burn. I was also shocked to find that same following
morning that my heater had failed in the polytunnel. There was ice
everywhere, which was soon defrosted by the fiery language that
followed, of which I couldnt possibly repeat in a family magazine
like this one. Ravenea rivularis and Coccothrinax barbadensis had
been totally destroyed, with most of the leaves being lost to the
low temperature. However, I think they will recover as the new spears
seem to have remained intact. Howea forsteriana had suffered about
20% tip burn. It took me the following weekend to sift through the
debris, but to my surprise I didnt lose a single palm, and
a few weeks later, they still seem to be alive. All the other palms
have come through OK. Caryota himalaya is actually growing, if very
slowly; Syagrus romanzoffiana and Livistona Saribus look great,
although they did sustain some damage; Phoenix roebelenii and P.
theophrasti are untouched; as are Rhopalostylis sapida, Chamaedorea
microspadix and C. radicalis, and an X Butiagrus hybrid.
Like most of you I long for spring and the return
of warmer weather, watching as our beloved palms spring back into
life, rewarding us with the new growth that we seem to have waited
half a year for. But, call me mad, in a way I am looking forward
to next winter so I can begin my experimentation process again!
Im looking forward to trying some of the Andean rain forest
palms, such as the high altitude Ceroxylon varieties and some more
unknown forms of Chamaedorea. Indeed there are quite a few species
that look promising, such as Geonoma weberbaueri and jussieiana,
found growing at elevations of over 3000m up in the Andean mountains
where it is cool and cloudy for a good part of the year. Also worth
trying are some varieties of Attalea, Allagoptera, and Acrocomia
that come from various other locations in South America. Hedyscepe
canterburyana and Lepidorrhachis mooreana from Lord Howe Island
also seem to have a lot of promise. If I manage to obtain these
palms, I will keep you posted on the results.
Palms in the summer
I personally think seed propagation is great when
it comes to growing palms, and late winter/early spring is a time
when I like to really get going sowing all those new palms seeds
you just seem to keep acquiring. Ive almost perfected the
art of palm seed propagating (well I got there eventually), but
there are a few rules to follow that you may well know. For those
of you who dont, the most important rule of all is to buy
fresh seed. The best sources are usually suppliers that sell them
in bulk, or give an availability period, as they are more aware
of the loss of viability in palm seed thus only keeping fresh stock
at the times of year that they are available. Second, forget the
myth that palm seed is impossible to germinate; about 95% of palm
species will sprout without any problem at all. Personally I favour
the sphagnum moss method: soak the seeds for a day or two in clean
water, changing it every now and then (to remove any inhibitors)
and checking that any old fruit flesh has been removed. Then take
a zip bag, and half fill it with moss that has been soaked in water
and then squeezed out (a rolling pin works well here), and dont
forget tofluff the moss back up before putting it in
the bag. Once this is done, place the seeds in the bag and put them
in a warm place (between 30-35°C).
I actually have a daylight lamp in my germinating
cupboard as well, which prevents any seeds that come up from getting
elongated. I usually check the seeds about once a week. If the moss
starts to feel a bit dry, I just tip the lot out (carefully!!!)
and re-moisten it.
Ive found that 4-6 weeks is the usual incubation
time, although some do take longer. These include Attalea, Acrocomia,
Jubaea, and Allogoptera, which can take anything up to 2 years,
although so far I have managed to get at least one of each to germinate
in less than 6 months. Phoenix, Washingtonia, and Copernica seeds
are about the easiest seeds I have ever germinated; they usually
taking less than 4 weeks. Trachycarpus and Jubaea can be germinated
in the same way although I would recommend a temperature of around
20-25°C, as they seem to germinate better. The only seeds I
would recommend sowing in a soil based compost are those seeds that
grow long tap roots, such as Borassus and Bismarckia. These need
a deep root run into the soil, but can be fooled into thinking that
the roots are deeper than what they actually are. The growers in
the US actually use a process of raising Borassus seeds by growing
them in pots about 18" deep. The tap root will eventually hit
the bottom and form a blob. The pot is then carefully
knocked out, the seed and root are repotted with the blob just below
the surface, and the seed is allowed to hang free attached to a
frame or some other kind of support. The first leaf will then emerge
from just below the surface allowing the root to grow down another
18". I have used this technique with some success, although
the roots do tend to rot easily. However, damage to the tap root
is not terminal as long as the seedling has developed some fine
roots.
Bismarkia is similar in some respects and can be risen up, though
they only require a root run of about 12" in the initial stages.
Living in our part of the world isnt such a
bad thing. There are days when my enthusiasm subsides, but for the
most part Im always kept going by the fact that there is so
much to learn and there are so many palms to try. The way global
warming is coming along, in years to come maybe many of us wont
have to worry about hard frosts threatening our prize palms. Who
knows, maybe our part of the planet will become a flowering tropical
oasis. But as for me, I cant wait that long. Experimentation
is part of the fun, and as they say, If you never try, you
will never know.
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