by Glenn Davis, UCCE Master
Gardener, El Dorado County
April, 2003
At this time of the year I have just planted a new fruit tree
with what promises to be the best and latest in fruit development. If I have
correctly followed all of the planting directions the little “dog-leg” at the
base of the tree is a few inches above ground and the stub of the rootstock is
facing the protected north. Most of the fruit trees available in nurseries are
the result of a scion grafted onto the rootstock that can best handle the soil
conditions of our area. The rootstock can also help to determine whether the
tree will be a standard, semi-dwarf or dwarf tree.
Pure fruit trees, grown from seed, are hard to come by and all
too often have fruit that reverts back to their origin; seed grown trees do not
always produce the fruit of the parent. If you want the fruit of a certain tree
you must choose a tree that has been grown from the wood of the original tree. In
gardening terms this is called asexual reproduction; you don’t need flowers,
bees and pollination; you just join two pieces of wood together. Most of us
know this as “grafting” a method of propagation that does not need to go
through the entire growth cycle of a tree.
Grafting is a way of making sure the new plant reproduces the
fruit, structure and characteristics of the plant you are propagating. The type
of rootstock can control the size and with careful planning you can vary the
fruit and flowers on any individual plant. If the graft is onto a very vigorous
rootstock the plant will react accordingly and grow faster and the flowers and
fruit will develop quicker; grafted scions onto established plants frequently
do better because they are nourished by a mature plant. One of the appealing
features of grafting for the home gardener is the possibility of having a
single tree that can produce a variety of fruit in a very small area.
As in any plant work there are a couple of caveats when you
graft. Rejection of the grafted scion can occur and the graft union itself can
be extremely fragile. Sometimes rootstocks can sucker and leave you with a
small forest of buds at the base of the plant.
Most grafting is done in the spring of the year and the scions
that are used are second year wood with good leaf buds. If you have a problem
identifying a flower bud from a leaf bud, flower buds are plump while leaf buds
are long and narrow. The best scion wood seems to come from the middle of the
selected branch; terminal wood lacks nutrition while the base wood is a little
too mature. With the exception of whip grafting, the best scion wood is usually
about ¼ to ½ inch in diameter; above all the scion should not be larger than
the stock.
Once the graft has been completed you must cover the graft to
protect it; in the old days beeswax was used. I recently asked a nursery for
some grafting wax and they suggested I use plastic wrap instead. There are a
great many substitutes for grafting wax; grafting tape, rubber electric tape,
freezer tape, or any plastic wrap will do. The best cover is one that will
disintegrate by itself once the graft has taken; you have to make sure the wrap
is flexible and can expand with the growth of the tree and will not girdle the
branch in the future. Other than a wrap to cover the graft the only tools
needed for grafting are a pair of pruning clippers and a very sharp knife.
There are a lot of different grafting techniques and each has
been developed to perform a different function. Grafting uses a wood branch or
scion while bud grafting uses a very small bud from the branch. Root and stem
grafting are usually the type preferred for small plants. Crown grafting is the
type of grafting used to establish a variety of fruit on a single tree. Bark
grafting is the type that is used when attaching a scion to rootstock while
veneer grafting is most often used for evergreens. Cleft, saddle, splice and
whip grafting are some other types of grafting you might want to explore.
While it is fun to graft using illustrations from a book, the
best method is to work with someone who has done a lot of it. If you are
interested in learning more about grafting and getting a little hands on
experience, watch the local newspaper for announcements of grafting classes given
by the University of California Cooperative Extension Master Gardeners. For
more information on any backyard gardening topic, contact the Master Gardeners
Office, (530) 621-5512, Monday through Friday, 9:00 AM to Noon.