Grafting cedars - a new cultivar of Cedrus deodara? - Lincoln ...
Grafting cedars - a new cultivar of Cedrus deodara? - Lincoln ...
Grafting cedars - a new cultivar of Cedrus deodara? - Lincoln ...
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<strong>Grafting</strong> <strong>cedars</strong> – a <strong>new</strong> <strong>cultivar</strong> <strong>of</strong> <strong>Cedrus</strong> <strong>deodara</strong>?<br />
Roy A. Edwards Feb. 2009<br />
Introduction<br />
A sport arose on a <strong>Cedrus</strong> <strong>deodara</strong> (Himalayan cedar) at <strong>Lincoln</strong> University about the year 2000. I<br />
observed this for a period <strong>of</strong> possibly five to seven years before finally getting around to grafting <strong>of</strong> it<br />
onto seedling trees <strong>of</strong> the same species. Brent Richards obtained seedling trees for me in early 2008<br />
and these were grown on at the <strong>Lincoln</strong> University nursery.<br />
Sport first noticed around 2000<br />
Sport growth by 2007, this sport looks as though it would make a good weeping bun shaped conifer.<br />
There does not appear to be a <strong>cultivar</strong> <strong>of</strong> the Himalayan cedar that is similar and available in New<br />
Zealand. Palmer (1990) briefly describes both a weeping blue cedar <strong>Cedrus</strong> atlantica ‘Glauca<br />
Pendula’ and also a cedar <strong>of</strong> Lebanon as <strong>Cedrus</strong> libani ‘Sargentii’. Hilliers (1977) describe a <strong>Cedrus</strong><br />
<strong>deodara</strong> ‘Pendula’ as a wide-spreading low bush with pendulous branching, this selection appears<br />
more likely to be a more upright bun shaped weeping example. Cedar Lodge Nurseries web site<br />
(2008) lists a number <strong>of</strong> <strong>cultivar</strong>s <strong>of</strong> <strong>Cedrus</strong> <strong>deodara</strong>, it is possible this sport is similar to one <strong>of</strong> the<br />
following listed ‘Mountain Beauty’, ‘Mylor’ or ‘Pendula’. These will need to be checked before any<br />
decision to register a <strong>new</strong> <strong>cultivar</strong> is made.
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Method<br />
Early in 2008 seedling growing on lines <strong>of</strong> <strong>Cedrus</strong> <strong>deodara</strong> were purchased and grown on at the<br />
<strong>Lincoln</strong> University nursery. In late July (mid winter) twenty <strong>of</strong> those seedling trees were brought into<br />
the Fletcher House (a durolite covered heated greenhouse) to encourage early root growth. On 20 th<br />
August 2008 scion material <strong>of</strong> the sport was collected and Brent Richards and myself side veneer<br />
grafted that material onto the seedlings. The grafts were made at around 60mm from the base <strong>of</strong> the<br />
tree and the grafts were secured by tying with ‘Buddy Tape’. The grafts were not sealed or waxed.<br />
Plastic bags were placed over the whole seedling tree and left open at the base. The grafted trees were<br />
placed under a propagating tent with intermittent mist and base heat <strong>of</strong> around 20°C. Mist nozzles<br />
above the bags were turned <strong>of</strong>f, but nearby nozzles were on for cuttings <strong>of</strong> other species. The trees<br />
were kept in this warm, high humidity environment until the 10 th September (a period <strong>of</strong> 21 days).<br />
The trees were then placed on the floor <strong>of</strong> the Fletcher House and two <strong>of</strong> the twenty trees had the<br />
plastic bags removed. All <strong>of</strong> the remaining bagged trees had the bags removed on the 22 nd September<br />
after no adverse effects were noted from the earlier two that had the bags removed. All trees had<br />
shown signs <strong>of</strong> a strong flush <strong>of</strong> growth at this stage. All grafts looked as though they were also<br />
healthy and likely to take. In the absence <strong>of</strong> specific information about when heading back <strong>of</strong> grafts<br />
should be done they were not headed back until the 13 th October (54 days after grafts were made)<br />
when it was assumed sufficient time for the grafts to have properly taken. The trees were headed back<br />
above the “Buddy ties’ so these were not disturbed at this stage. Cuts were made on an angle between<br />
10 and 15mm above the graft. Cuts were not painted or sealed. The grafted trees were moved into a<br />
durolite covered house, but without any heating on the 15 th October. One half <strong>of</strong> this house is covered<br />
with durolite, the other half is covered with shade cloth only.<br />
Side veneer grafts were used as suggested in Hartmann et al. (2002). Because <strong>of</strong> the difference in<br />
diameters <strong>of</strong> the stems <strong>of</strong> the scion and the rootstocks cambium layers were matched on one side <strong>of</strong><br />
the graft only.
Side veneer grafts tied with ‘Buddy Tape’<br />
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The rootstocks were headed back 13 th October, 2008. The scions above had clearly made good growth<br />
indicating a successful graft, the tape will be removed in late summer 2009.
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By February 2009 only 11 <strong>of</strong> the 20 grafts (55%) had survived and were growing well. It was clear<br />
that although the grafts had seemed to have taken that other reasons contributed to failures occurring.<br />
Based on observations, the possibilities included grafts were removed from the high humidity<br />
environment too soon (least likely), grafted plants were removed from the Fletcher house into the<br />
shade house too soon (slightly possible), some containers in the shade house were observed to be<br />
quite dry in October and some grafts were showing signs <strong>of</strong> severe stress then (highly probable).<br />
Severe frost in late October or early November occurred (slightly possible), plants were put out in an<br />
open, wind sheltered area over the summer – dried out or other extremes <strong>of</strong> heat, cool (slightly<br />
possible).<br />
Summary.<br />
Overall this was a useful exercise, it appeared as though the timing and grafting methods were<br />
satisfactory and all grafts showed initial signs <strong>of</strong> having taken. It appears as though the critical period<br />
is in the weaning <strong>of</strong>f <strong>of</strong> the grafted plants into a harsher environment. A longer period in a warmer<br />
more sheltered environment may aid the final success rates.<br />
Acknowledgements.<br />
I would like to thank Brent Richards <strong>of</strong> the <strong>Lincoln</strong> University Nursery for obtaining and growing on<br />
the seedling Himalayan <strong>cedars</strong> used for the rootstocks and his assistance in grafting the trees and their<br />
after care. I would also like to thank Shane Timbrell from the Grounds Department at <strong>Lincoln</strong><br />
University for collecting the scion material from high up in an established Himalayan cedar.<br />
References<br />
Cedar Lodge Nurseries web site. www.conifers.co.nz/conifer_lists.htm<br />
Hartmann, Hudson T., Kester, Dale E., Davies, Fred T., Geneve, Robert L. ‘Plant<br />
propagation : principles and practices’ 7th edition. Upper Saddle River, NJ : Prentice Hall,<br />
2002.<br />
Hillier & Sons ‘Hilliers’ Manual <strong>of</strong> Trees & Shrubs’ Fourth Edition. David & Charles (Publishers)<br />
Limited, Brunel House Newton Abbot Devon. (1977)<br />
Palmer, Stanley J. ‘Palmers Manual <strong>of</strong> Trees and Shrubs’ Lancewood Publishing, P.O. Box 1105,<br />
Runaway Bay, Queensland 4216, Australia. 1990