Grafting Citrus Trees – Cleft Grafting a Fruit Cocktail Tree


This video will show how to graft citrus
trees using the cleft graft. I will use the cleft graft to add a new
variety to an existing tree to create a multi-variety citrus cocktail tree. This is the tree that I will be
grafting to — an Oroblanco pummelo hybrid tree. I’ll be grafting a Sarawak pummelo scion. I like to use the cleft graft when the
scion is the same size or slightly smaller than the target branch. I ordered my Sarawak scions from California’s citrus budwood program,
the CCPP. So that my graft succeeds and also
to prevent the spread of disease, I sterilize my tools between grafts using
chlorine bleach at a concentration of 1.5%. Cutting the target branch with a saw creates a minimum amount of damage
at the end of the branch. Next I split the end of the target branch
to create the cleft into which the scion will be inserted. I begin at the middle of
the end of the branch and slowly rock the knife back and forth
until the cut is the desired length. This cut is about 1.5 inches or
4 cm long. Now I will pick
the flattest side of the scion to match the cleft in the target branch. I will cut it to a tapered point for
insertion into the target branch. In recent years, huanglongbing or HLB,
the most deadly disease of citrus trees, has been spreading rapidly
throughout the world. Invasive insects called citrus psyllids
carry the disease from one citrus tree to another. Human movement of
citrus trees, cuttings, and leaves has sped the spread of the disease
and the insects around the world, resulting in the deaths of
hundreds of millions of citrus trees.
Because of disease, it is very important
to understand the local situation before grafting citrus. Local laws may require the use of
registered disease-tested budwood when grafting citrus. For example, the threat of HLB is so
severe in California that the state mandates the use of
registered budwood whenever citrus trees are grafted. The only source of registered budwood
for hobbyists in California is the CCPP. The linked video shows
how to order budwood. Theyzz will ship citrus budwood anywhere in
the world where the local laws allow it. If the local laws do not allow it,
there may be a local budwood program. fruitmentor.com/CitrusBudwood has a list. At the very end of the video
I will have more on huanglongbing in different parts of the world. As I insert the scion
into the target branch, my goal is to line up the cambium of the
scion with that of the rootstock. The cambium is a thin layer of tissue
between the bark and the wood. For the graft to succeed,
the cambium layers must touch. I’m going to show how I have lined up
the cambium layers via an animation. The bark of the scion may be a different
thickness than the bark of the rootstock. So if the outside of the bark is lined up,
the cambium layers may not be in contact. By adjusting the angle of the scion,
it is easy to guarantee that the cambium layers are touching in
at least one point. Here I wrap the graft with an initial
layer of parafilm to seal the graft and hold it in place. To get a good seal, I gently pull on
the parafilm as I wrap it. This makes it stick to itself. In order to ensure close contact
between the cambium layers and to strengthen the graft
while it is healing, I wrap it with a rubber band. Here I prune the scion to leave
three or four buds. The next step is to wrap the graft with
a second layer of parafilm. I wrap starting from the bottom,
overlapping as I go up, and gently pulling on the parafilm
to make it stick. Overlapping the layers keeps
the graft from drying out and will also keep out rainwater. Other than the buds, I completely wrap
the scion, including the cut end. Here I add a label with the name of the
variety and also the date of the graft. In order to keep the graft from
drying out, I wrap it with aluminum foil which reflects the sunlight
and keeps the graft from getting too hot. After a three week healing period,
I remove the foil and see that the graft is still green. The time-lapse video shows about
four months of growth of the graft. Unwrapping shows that
the graft has healed well. This includes the back side where there
was no attempt to match the cambium. In addition to this video, you can find a
step-by-step guide with more details at: http://fruitmentor.com/CleftGraftingCitrus Here’s the whole Sarawak branch. I have patch budded
a pummelo called Mato Buntan. I have also cleft grafted
a pummelo called Hirado Buntan. I have made this video to stop the spread
of huanglongbing. Spreading the word about
the importance of using budwood that has tested free of disease
will save trees. Please help by sharing this video. Also please be sure to give the video
a “thumbs up”. You can also help by subscribing to this
YouTube channel. Also be sure to check out my other videos on: Bud Grafting Citrus, Z-Grafting Citrus, Growing Citrus from Cuttings, and Ordering Citrus Budwood. You can download a free eBook with tips
for successful citrus grafting at: http://fruitmentor.com/GraftingTips I have created this map to show
the worldwide spread of both huanglongbing (HLB disease) and also citrus psyllids,
the insects that spread the disease. Please keep in mind that this map reflects
the situation at the beginning of 2016 and will become out-of-date as
this video ages. Even in 2016 this map will be inaccurate. One reason for this is that trees that
have the disease and are spreading it often display no symptoms and test negative
even with a state-of-the-art test. Another reason is a lack of surveys in
areas where the disease and insects may be present. Huanglongbing is a new disease of citrus
that originated in the 20th century. There are two main strains of the disease: one that originated in Asia, and another form
that originated in Africa. Two types of citrus psyllids
transmit the disease: again one that originated in Asia
and another that originated in Africa. By the end of the 20th century
huanglongbing was widespread in Asia, greatly reducing the life expectancy
of citrus trees in Asia. Red areas of the map show where both Asian citrus psyllids
and Asian HLB are present. Asian citrus psyllids were
first detected in Brazil in 1942. The psyllids arrived without the disease
and spread in South America as a minor nuisance for many years. HLB was first detected in Brazil
in 2004 and quickly spread with devastating results. Tan areas of the map show where the asian citrus psyllid
is known to have spread,
but where HLB is not yet known. Grafting with infected budwood
in Tan areas will cause a devastating outbreak of disease. Asian citrus psyllids first arrived
in Florida in 1998. HLB was first detected in Florida
in 2005 in Miami. HLB spread much more rapidly
in Florida than in Brazil due to the shipment from Miami of large
numbers of plants all over the state. These included
HLB-infected nursery plants and plants infested with
HLB-positive psyllids. In the commercial citrus farming zone
of Texas in 2012, HLB was first detected in a farm
near the border with Mexico.
The disease spread quickly. The lesson available from
the devastation in Florida is that citrus nursery trees
in areas with citrus psyllids
must always be sourced
from insect-resistant structures. Unfortunately citrus nurseries
in Texas were slow to change. In 2013, more than 10,000 open-air
citrus trees were shipped to Houston from a nursery in the citrus zone
where psyllids were present, but outside of the area
quarantined for HLB. More than 5000 of those trees
were sold to homeowners. Many of the remaining trees tested
positive for HLB in Houston nurseries. At this point HLB could be
anywhere in Texas. In 2012 the first HLB-positive tree
was detected in California in a home-grafted multi-variety
citrus cocktail tree that had been grafted with
unregistered backyard budwood.
In 2015 more HLB-positive trees
were detected in California, causing an expansion
of the quarantine zone. In the expanded quarantine zone, the California Department of
Food and Agriculture discovered an illegal citrus nursery with thousands of illegally-grafted
open-air trees on hand. Although the discovered trees
were destroyed, trees made illegally before the discovery
were undoubtedly sold. At this point HLB could be
anywhere in California. HLB is now present in the
major citrus farming areas of Mexico. The first discovery of the African form
of HLB was in South Africa in the 1920s. Purple areas of the map show where
both African citrus psyllids and African HLB are present. Yellow areas of the map show where
the african citrus psyllid is known to have spread,
but where HLB is not yet known. The african citrus psyllid
has recently been discovered in Northern Portugal
and in Northwestern Spain. Movement of citrus plants and
citrus relatives such as curry leaves outside of this area has the potential
to devastate citrus all over Europe. In laboratory settings,
the african citrus psyllid has been shown to spread
all forms of HLB. Although Australia
has its own assortment of native diseases and insects
harmful to citrus trees, HLB and citrus psyllids
are not currently known there. Let’s stop HLB from spreading
any further in California or any other place in the world.

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