Little or large??

Discussion in 'Gymnosperms (incl. Conifers)' started by Luke Harding, Aug 13, 2008.

  1. Luke Harding

    Luke Harding Active Member

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    Westonbirt Arboretum, Great Britain
    Hi Folks,
    I am currently looking into the possibility of propagating the Calocedrus decurrens 'Compacta'. According to the Illustrated encyclopedia of conifers by DM van Gelderen and JRP van Hoey Smith, this tree originated at the arboretum I now work at. It is described as a leaderless and compact form. Before taking a look at our own tree I decided to look it up on the net. It is described everywhere as a dwarf and compact tree which is globe shaped and flat topped. 'Nice' I thought, 'I'll take a look at ours to see how it is getting on'.
    We only have one left, so after a bit of fruitless searching for a small/dwarf conifer I had to resort to looking at more detailed maps to get its exact location. Imagine my surprise when I found our one and only 'Compacta' right next to our staff room, the tree which I used to park my old motorbike under!
    I'd hazard a guess that it is around 20-25ft high and has a trunk at least 8ft in height before the first branches. Indeed it is leaderless and the crown is compact but a dwarf it is definitly not!!
    My question is, does C.decurrens 'Compacta' always reach this size or is there another, smaller form propagated worldwide with the wrong name applied?
    I also noted that there is a form named 'nana'. Have the two been mixed up somewhere along the line?
  2. Ron B

    Ron B Paragon of Plants 10 Years

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    WA USA (Z8)
    It is common for slow-growing conifer cultivars to be described as dwarf. How old is the 'Compacta' there? It may have taken a long time to reach the size it is now.
  3. mr.shep

    mr.shep Well-Known Member 10 Years

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    San Joaquin Valley, California
    Compacta, Nana and Intricata are not the
    same in their growth habit. Then again if
    we look in the van Gelderen Conifers book
    we will see a major difference in the growth
    habits of the two principal trees, one being
    a columnar shape and the native plant for us
    being a much more pyramidal shape. There
    has been some doubt among a few people that
    the Libocedrus and the Calocedrus may not
    be the same plant anyway. Needle colors of
    them and the Winter coloration and in some
    areas trunk bark colors are not quite the same
    on them.

    It is going to be tough to sort out from the
    current published information how Compacta
    differs from Nana and how Nana differs from
    Intricata. I've seen Compacta that you know
    and I've seen Intricata from the Noble collection
    a few times, twice hands on and I've owned
    Nana. The larger sized plant of the three is
    Compacta, the smallest tree is the Intricata,
    the more pyramidal shape is the Nana. Think
    of Nana as looking like a native Calocedrus
    but much smaller in size, can get up to 12
    feet, 4 meters in height in 30 years in the
    ground, considerably smaller still if they
    are container grown (about 2 meters tall in
    30 years). Intricata is only going to be around
    2 feet tall in 30 years in the ground and is
    a much denser growing plant (much shorter
    nodal length and more twiggy) than Nana.
    Both Compacta and Intricata make a globe
    shape and generally are wider than tall.
    Nana of the ones I've seen are usually
    slightly taller than they are wide.

    Can a 20-25 foot tall tree still be considered a
    dwarf form and that depends on who we learned
    Conifers from and who they felt had the better
    reasoning behind what was a dwarf and what was
    a semi-dwarf. If we look in the Hillier Dwarf
    book and the Welch Dwarf Conifers
    book we may read some differing opinions
    in what constitutes a dwarf Conifer. One
    opinion is that to be a dwarf the Conifer had
    to stay under 6 feet tall, 2 meters, at an age
    of 20-25 years, whereas the other opinion
    is that some Conifers can still be a dwarf
    even when they are 25-30 feet tall after
    30-40 years of age. Also, a lot depends
    on whether the tree was ever grafted and
    whether seedlings from the selected or
    found cultivar came from a parent plant
    that never had been grafted. The issue
    here is that some Conifers could have
    come from a parent plant that had always
    been propagated from rooted cuttings
    and then germinated seed and lo and
    behold that 5 foot tall 25 year old
    specimen could yield seedlings from
    it that could attain heights of 20-25
    feet in 20-25 years. So, if we conclude
    that the parent plant is a dwarf then
    the cultivated progeny seedlings from
    it must be semi-dwarf. Some people
    feel the so-called pureline seedlings
    are still a dwarf plant, whereas others
    felt the seedlings cannot be a dwarf
    by virtue of their size. Still, the seedlings
    are much smaller in height than the
    species form plants are at the same
    ages. It is like comparing a Fat Albert
    Blue Spruce to a normal Blue Spruce
    and then take into consideration one
    plant may be 20 feet tall at a certain
    age and the other may be 40 feet tall
    at the same age. Is the 20 footer a
    dwarf form compared to the standard
    and the answer is yes. But, is the 20
    footer a true dwarf form and to me it
    is not but my opinion here does not
    count for much.


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