Root Grafts for Bonsai
Grafted plants for bonsai often present problems in the training stages, or later as the plants get older due to differing rates of growth between the root stock and scion and because of differing bark characteristics. This can be overcome by using cutting grown material whenever possible, or by using special types of grafts that will minimize the problems.
Avoiding Grafts
I try to avoid grafts for bonsai whenever possible. It is almost always better to have a plant on its own roots than grafted to a rootstock. Cutting grown material is becoming much more common for bonsai suitable species and you should look for it to avoid the problems of suckering and rootstock scion mismatch.
Suckering problems occur in such genera as Liquidambar, Malus (apple), Pyrus (pear), and Prunus ( cherry, plum, apricot), Crataegus (hawthorn), and others deciduous woody plants. Profuse suckering leads to endless pruning and bud rubbing to keep the suckers from overrunning your cultivar. The problem is particularly bad after major pruning, for example, after a trunk chop to get a low curve and taper to the trunk. Sometimes the scion will actually die and the understock will take over the plant after such drastic pruning.
In addition, there is often an unsightly graft union in these plants. The differing bark characteristics can make the union stand out dramatically and detract from the trunk, and the illusion of an ancient rugged tree. Growth rate mismatches can often lead to a 'necked down' appearance for smaller dwarf cultivars on standard rootstocks, exactly the kind of plants we are looking for in bonsai. Even worse is the problem of the scion growing faster, resulting in REVERSE taper. Prunus species often form a burl at the graft union that is prone to insect damage and completely unusable for bonsai purposes.
Most of these species can be grown from cuttings without too much difficulty. Some are extremely difficult, such as cultivars of Crataegus (hawthorn). Crataegus laevigata 'Paul's Scarlet' cuttings will sometimes take three years to root. It is also possible to air layer many of these species to get them on their own roots.
Conifers present the larger challenge. While most Juniperus, Chamaecyparis, and the broad leaf evergreens can be grown from cuttings, it is the pines that pose the greatest problems. Some pines can be grown from cuttings, but it is almost always easier to graft them.
Avoiding Grafts
I try to avoid grafts for bonsai whenever possible. It is almost always better to have a plant on its own roots than grafted to a rootstock. Cutting grown material is becoming much more common for bonsai suitable species and you should look for it to avoid the problems of suckering and rootstock scion mismatch.
Suckering problems occur in such genera as Liquidambar, Malus (apple), Pyrus (pear), and Prunus ( cherry, plum, apricot), Crataegus (hawthorn), and others deciduous woody plants. Profuse suckering leads to endless pruning and bud rubbing to keep the suckers from overrunning your cultivar. The problem is particularly bad after major pruning, for example, after a trunk chop to get a low curve and taper to the trunk. Sometimes the scion will actually die and the understock will take over the plant after such drastic pruning.
Most of these species can be grown from cuttings without too much difficulty. Some are extremely difficult, such as cultivars of Crataegus (hawthorn). Crataegus laevigata 'Paul's Scarlet' cuttings will sometimes take three years to root. It is also possible to air layer many of these species to get them on their own roots.
Conifers present the larger challenge. While most Juniperus, Chamaecyparis, and the broad leaf evergreens can be grown from cuttings, it is the pines that pose the greatest problems. Some pines can be grown from cuttings, but it is almost always easier to graft them.
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