On Apr 7, 9:26*am, "brooklyn1" wrote:
"gardengal" wrote :

Clump birches are often "created" by the grower - they take multiple
saplings and plant them together in the same container or planting
hole, so they grow as if they were a multi-trunked tree. It's quite
common, as multi-trunked trees do not occur that way naturally with
great frequency.

That's just not true. *The number of trunks of clump birch is created by
selective pruning, not by planting multiple trees (could be done but no
reputible nursery would, that would be cheating), planting a number of birch
close together does not a clump birch make... usually only the most dominant
will survive, the rest will eventually die. *

So I guess 20+ years in the nursery industry, both in retail sales, as
a buyer and as a wholesale grower, speaks for nothing? Unfortunately,
you don't quite know what you're talking about.

"Reputable" nurseries do it all the time - it is an extremely common
practice to develop clump-form trees at rather young ages that would
take years to produce naturally. There's no "cheating" about it - it
is a common practice that is done with a variety of tree species to
create the look of a multiple trunked tree. And many birches, Betula
nigra in particular, do not produce multiple trunks readily in the
wild - they tend to be single trunk specimens under these conditions
although they do often grow in colonies. Pruning does not create the
same effect as it only encourages suckering shoots which seldom grow
into strong trunks. If you were to investigate the propagation methods
and separate the trunks of most of the commercially available "clump"
birches, you would find them growing as individual trees.

From Ohio State:
"Birches are usually produced and sold in clump form (also known as
multitrunked or multistemmed form), rather than tree form (also known
as singletrunked form), to further showcase their best ornamental
feature, namely their showy bark. In forest settings, singletrunked
forms predominate, which is the case for most shade or timber trees."

Note the word "produced".

and from a landscape nursery:
"Birches are usually clumped in multiples of three, four or five for
appearance sake. Clumping usually produces a tree with a crown or top
growth equal to a single tree with three smaller trunks. Single trees
can be clumped easier when smaller than as larger plants. If single
plants are to be clumped, carefully remove some of the soil around the
root system before planting. Water thoroughly after planting."

This technique, also known as "bundle planting", is very common in
Europe and has been for many years.
"The bundle planting technique is not new. Evelyn recommended it in
the 17th century to create wide spreading crowns quickly. Despite the
relatively common existence of notable specimens in earlier designed
landscape and specimens growing naturally in almost every semi-natural
woodland, many of today's designers hold a curious suspicion that
trees, other than birch do not grow well in bundles. Or is it that
they have just gone out of fashion or are not readily available?"