You’re probably familiar with fruit cocktail, but what
about a fruit cocktail tree? Search yards in your neighborhood
and you might be able to find a tree that produces several
different but related fruits—one set of branches grows
plums, another peaches, and another apricots for example. This
tree of plenty may be an elegant and sophisticated presentation
of nature’s bounty, but the method behind its creation
is ancient and rather crude: Cut a bit from one tree and wriggle
it into the wound you make in another. Bandage, wait a season,
and behold—a new tree.
||Grafting is, at its simplest, wounding and healing. It’s
the gardener’s way of taking advantage of a tree’s
natural repair mechanisms. The growth of a trees trunk and branches
occurs in a layer called the cambium, a greenish tissue that lies
just under the tree’s protective bark. One unique talent
of the cambium layer is that if it’s cut or torn, the two
pieces will grow back together again. Grafters make use of this
by cutting parts of the trees they want to graft together—taking
a branch cut from one tree and putting it over the spot where a
branch has been removed from another—and securing them in
such a way that their cambium layers are in contact with each other.
Over time, these layers will grow together, and the grafted part
will become just another branch of the tree.
There are some good reasons to put a tree through all this injury
(besides getting it to grow three different fruits). Consider orange
trees: the roots of the tree that produces the sweet orange
that we know and love can take up a virus that effects the growth
of tree bark. The roots of the less-loved sour orange, however,
won’t accept this virus. So by grafting sweet orange buds
onto sour orange trees, growers in places like Texas protect their
crop from disease. Grafting can make trees resistant to a variety
of factors, including cold, drought, and microbes.
A second reason to graft is that some tree families, such as citrus,
don’t reproduce reliably. Oranges,
for example, are either seedless, or are hybrids that may produce
a tree that is somewhat different from its parent. Grafting gives
growers a simple way to reproduce fruit trees without having to
rely on seeds.
© Bonfante Gardens
farmers and gardeners probably got the idea for grafting from nature
itself. Young trees that sprout close together may graft as they
grow up. Occasionally the branch of one tree will grow into the
crook of another, and the pressure will injure the bark enough
to allow the trees to graft. The creeping fig tree will graft its
own branches in a tangle around another tree it uses for support.
Other plants, such as rubber trees, are known to graft with each
other at the roots. There are records of gardeners grafting in
China and Mesopotamia as early as 2000 BC. Grafting was common
in ancient Greece. In Renaissance England, grafters began making
tree sculptures, and some artists and horticulturists continue
the tradition today.
For pictures of some fanciful grafts, check out the Circus Trees
at Bonfante Gardens in Gilroy, CA: