Bridge Grafting Steps; Buttress Grafting Steps
Table of Contents
Bridge Grafting or Buttress Grafting
Today, we are providing information of Bridge Grafting/Buttress Grafting.
Introduction:
What is Bridge grafting? It is a method of grafting used for repairing damage to the bark of a tree. This method is best done in early spring when the bark is slipping. Scions are taken from dormant 1-year old stems. Bridge grafting is also called Buttress grafting.
Bridge grafting is used to “bridge” a damaged area of a plant, generally at or near the base of the trunk. Such damage normally results from contact with grading or lawn maintenance equipment or it may be caused by rodents, cold temperatures, or disease organisms. The bridge graft provides maintain as well as a pipeline that allows water and nutrients to move across the damaged area.
Bridge grafts are generally done in early spring just before active plant growth begins. They may be complete any time the bark of the injured plant “slips.” Some examples of the Bridge grafting used fruit trees are apples, citrus, mangoes, and pears.
Things required for Bridge Grafting:
The Materials used for Bridge grafting is;
The following material will be required to complete a Bridge graft:
- Before collecting scions.
- Grafting wax to protect the grafts from drying out.
- A sharp knife to shape the scions, trim the wound & cut the bark.
- Small brads about one inch long to hold the scions in position.
- A short block of wood 3/4 of an inch in thickness to help forms a bow.
Bridge Grafting steps:
The steps for Bridge grafting are;
A Bridge graft is used to provide nutrients to the rootstock of a woody perennial when the barks, & then the conductive tissues, have been detached from a branch of the trunk. This wound is often caused by rabbits or other rodents, stripping the bark away & girdling the tree. The inability of the plant to transport food contrived in the leaves down to the root organism, causes the root system to die & in the death cycle, the resulting lack of root system causes the upper portions of the plant to die. Where one-quarter or less of the trunk circumference has been girdled, it may not be essential to use this technique. It is difficult on small caliper tree trunks.
A Bridge graft or Buttress graft uses scions to ‘bridge’ the gap. Each scion is taper cut in order to accommodate the required for matching the cambium layers of the scion with those of the tree being repaired. Once in place, the graft wounds must be totally sealed to prevent moving of tissues which would inhibit them from combination together & to stop dissection of the site which would lead to the death of the scions.
To proceed with Bridge grafting, following steps requires to be done first:
- Collect the scion wood (in anticipation of the damage)
- Inspect the damage
- Prepare the area around the tree to be grafted
- Perform the grafting.
The first two steps must have been done along with the winter pruning or as soon as possible in early spring. It is necessary to collect the scion wood from the dormant trees.
The last two steps are performed in May month when the bark is “slippery” and is easily separated from the cambium without any damage to the bark or cambium. If the injury is right at the soil line or slightly below, one must dig down to the healthy part. It must be left exposed to the sun so it can warm-up & become “slippery”. This is done at least ten days prior to grafting to ensure high and good take or healing.
Read: Wedge Grafting Steps/Cleft Grafting Steps.
Time to Grafting:
The best time for Bridge grafting is;
Sometime after the buds start to swell in the spring, the bark will peel back or slip easily. The tree is now prepared to be grafted. Growth is going on at this time & the scions are less likely to dry out. Occasionally scions are inserted through the summer to replace some that failed.
Preparing the Wound for grafting:
Trim loose & dried bark from the tree. Reshape the girdled area so as to depart a smooth edge. It does not have to be straight across the tree, but can be gently curved to follow the form of the wound.
Mark two parallel cuts in the tree bark about two inches long & the width of the scion. Remove about one and a half inches of the bark, leaving a small flap. Repeat the procedure on the opposite side of the girdled area.
Preparing the Scion:
For scion preparation in Bridge grafting, use dormant water sprouts or terminal development from the previous season. They should be about the thickness of n lead pencil and four to five inches longer than the gap they are to bridge to allow for beveling of the ends. When they are in place, they must arch slightly in the middle.
Bridge grafting generally is performed at about the time the trees are breaking dormancy and beginning to grow; you could have to collect scion material ahead of time. Scions must be stored in a refrigerator in a suitable medium to prevent drying. Select scions those are straight & about twice as long as the damaged area to be bridged. Make a one and a half to two inches long tapered cut on the same plane at each end of the scion.
Preparing the Stock:
Eliminate any damaged tissue so the graft is on healthy stems. Cut a flap in the bark of the rootstock the same width as the scion & below the injury to be repaired. Gently fold the flap left from the stock, being careful not to tear the bark flap.
Inserting the Scion:
First, include and secure the scion below the injury; push the scion under the flap with the cut portion of the scion beside the wood of the injured stem or trunk. Then go back and insert and secure the scion above the injury following these similar steps. Push the scion firmly into place. Pull the flap over the scion & tack it into place as described for bark grafting.
When grafting with young stems that can waver in the wind, contain the scions, so that they bow outward slightly. Bridge grafts must be spaced about three to four inches apart across the damaged area.
How to make a Bridge Grafting?
In the Bridge grafting procedure, the trunk of fruit trees can be damaged by different means. If the bark is removed the tissues that transport food manufactured in the leaves to the roots are removed. The root system, as a result, has no source of food & will slowly starve. The above-ground portions of the tree will gradually decline and eventually die as the root system uses up all reserves of energy & finally fails.
The bridge graft is a process of repairing a girdled trunk. Although it can be done by inserting the bridges into cuts prepared in the wood of the trunk, the common method is to lift the bark and place the exposed cambiums of scion & stock together. It is thus generally a bark graft and is not done until May. In this case, it is essential to collect the dormant scions earlier and store them until the repairs are to be made. Healthy, matured suckers of tough varieties are suitable.
Trees which have been in the orchard less than four years are usually too small for successful bridge grafting. If they are completely girdled, or nearly so, & there is still a collar of live bark above the graft union, saw the top off at a point immediately below the injury. Apple, pear, and plum will expand a new top without grafting. Cherry & peach are unlikely to do so and need grafting of scions on the remaining trunks, or preferably the planting of a new tree. Apple, pear, and plum, when cut back, will create many shoots. These shoots must not be thinned until they are a year old, then only the most suitable ones should be retained.
Of the numerous methods of bridge grafting, the channel or Inlay method is normally preferred. The two probable locations of the channel depending on whether or not the wound has been treated previously with a protective covering. Where the wound has been covered a little time before the grafting operation, the channels must be well above & below the treated area; otherwise, the method is more desirable, mainly with regard to the speed of the operation.
Arrange the scions with the bevel on the side opposite the natural bow of the wood. When a scion has been cut to the proper length & beveled for 5 to 8 cm at each end, it is laid over the wound in the position it is to occupy. By outlining the scions on the bark of the stock with the knifepoint, an almost great fit of the scions in the channels is possible. The distance between the extremities of the channels must be slightly less than the length of the scion, allowing for a slight bow of the scion when the job is completed. This slight bend allows better contact of scion and stock & reduces the danger of breaking connections if the tree sways with the wind.
With a screwdriver, lift & remove the strips of bark from the channels. If these strips do not approach away readily from the wood, postpone the work until they do. Place the lower (thicker) end of the scion in the bottom channel & nail it there with two 2.5 cm box or basket nails. Then spring the upper end into position & nail it similarly. Place scions about 5 cm apart over the injured area & then cover all wounded surfaces thoroughly with a good quality grafting compound that will not shrink or crack.
Read: Information On Agricultural Robots.
Spacing Bridge Grafts:
The Spacing the Bridge grafts three inches or less apart. They restore the passage of food & cover the sapwood from which the bark has been destroyed. The passage of food should be restored as soon as possible if the injury to the tree is to be held to a minimum. And the sooner the grafts envelop the sapwood, the better. Eventually, the grafts grow together & completely restore a smooth trunk surface.
When Bridge grafting or buttress grafting mice-girdled trees, you often see narrow strips of bark which the mice missed. Even though these are sometimes small, they are very valuable. They are more effective than bridges and cut down the number of grafts that might first appear essential on a girdled tree.
Care after Bridge grafting:
The Bridge grafting care will be as follows;
Protected all graft areas with warm grafting wax or grafting paint. During and after the healing period, remove any buds or shoots that expand on the scions.
Inspect the grafted areas occasionally the first year & remove if necessary. Rub off any buds growing on the scions as soon as possible & replace any scions that fail to grow.
Advantages of Bridge grafting:
The advantages of Bridge grafting are given below;
- Some trees end up developing more resistance to diseases & adverse conditions than other trees. This disease resistance & hardiness is transferred from the rootstock to the scion.
- Trees that have been grafted reach maturity sooner than trees that weren’t grafted, leading to blooming flowers & fruit much earlier.
- Bridge grafting is more labor intensive, increasing labor costs. But grafting is cheaper overall because the cost of the apparatus is lower than with growing a plant from a seed.
- Much of the quality found in the fruit, leaves & flower is retained, while these qualities are sometimes lost in plants that are grown from seed.
- Bridge grafting can be used to make large plants or smaller than what they were meant to be genetic.
Read: How To Grow Cowpeas.