Rootstock choice is important
It affects tree size, vigour, pest & disease susceptibility, staking requirements and preferred soil type.
We offer a number of dwarfing rootstock options in our apple range. The size of trees on each rootstock is expressed as a percentage of those grafted onto a seedling apple (seedlings of Granny Smith have been commonly used as rootstocks). This is a more reliable measure than a specific height as it takes account of variations in the vigour of different varieties and local conditions which both influence ultimate size.
How you care for, water and prune your tree is just as important in determining size and productiveness as rootstock selection.
Common apple rootstocks
The rootstocks shown in bold are used in our regular production. We can graft to order on any rootstock shown below.
M.27 : Height* to around 20% of seedling tree and yielding the ultimate dwarf apple tree. They are really lacking sufficient vigour to espalier, but are ideal to train as a stepover, a tree trained to a single wire about 50cm to 60cm above the ground. Each tree will not produce a great deal of fruit so their use is as much ornamental as productive. Used for our stepover range.
M.9 : Height* to around 35% of seedling tree, trees produce fruit within 2 years. Trees need staking or trellis support. M9 trees are susceptible to Woolly Aphid infestation. M9 is one of the most commonly used rootstock in commercial orchards in Australia and world wide. They are not ideal for organic production systems.
M.26 : Height* to around 40% of seedling tree, early producer. M26 generally need staking unless sheltered from wind and are susceptible to Woolly Aphid infestation making them less suitable for organic production. A good producer, may produce vigorous suckers and are reported to be intolerant of extended wet soil conditions. Used for our dwarf range where noted.
MM.102 : Height* to around 45% of seedling tree, growing taller in better soils, similar to M26 in average to poor soils. Early producer, long term staking not required. Quite resistant to Woolly Aphid making them ideal for organic gardeners. Used for our dwarf range.
MM.106: Height* to around 65% of a seedling tree, with moderate vigour and heavy cropping potential. Trees on MM.106 are well anchored, resistant to Woolly Aphid, adapt well to a wide range of soil types and climatic conditions, making it a very popular rootstock world wide. Used for our medium range.
Northern Spy: Height* to around 70% of a seedling tree, N.Spy was once one of the major commercial apple rootstocks due to its inherent resistance to Woolly Aphid and is still a popular rootstock in Australia. Used in breeding programs to produce the MM series of rootstocks in order to combine Woolly Aphid resistance with a strong dwarfing tendency.
MM.111: Height* to around 75% of a seedling tree, suitable for dry sandy soils, a good rootstock for poor soils and dry areas where extra vigor is required for better cropping. Suckering is low, and its resistance to Woolly Aphids is good. Used for our tall range.
M.793: Height* to around 80% of a seedling tree, produces trees that are better adapted to a wider range of soil types than Northern Spy. M.793 also produces trees that crop earlier and heavier than Northern Spy
There is some variation in opinions on rootstock size and our chart (below) is an attempt at coming up with a suitable guide for this part of the world. Check these website references if you feel like some not so light reading!
Orange Pippin - a respected UK fruit tree website
Eversen Nurseries – a commercial rootstock grower east of Melbourne
USDA-ARS - United States Department of Agriculture, Agricultural Research Service, Geneva, New York
Each of our rootstock options can be espaliered with MM.102 and MM.106 being ideal for the purpose. M9 is suitable for a compact espalier, perhaps no more than 1.5 metres wide while M26 can be maintained at a wider size.
We recommend Alan Gilbert’s book Espalier for an excellent explanation of how to create espaliers using a wide range of plants including many types of fruit tree.
Big is not necessarily best!
Beginning in 1912 The East Malling Research Institute in England selected and began trials of a range of rootstock material. Clones ranged from those with a very dwarfing influence through to those with aninvigorating influence on the cultivar. One of the interesting features of dwarfing rootstocks is that the dwarfing influence does not extend to the fruit. In fact fruit on younger trees is often larger.
The resulting Malling series, identified by the letter M followed by a number have gone on to play a major role in commercial apple growing throughout the world.
In 1928 work began on another equally important series of rootstocks when the East Malling Research Institute together with the John Innes Horticultural Institute began a program to produce woolly aphid resistant material, an attribute not found in the Malling selections. The resulting trees were named the Malling Merton series (denoted by MM and a number).
Some practical 'modern' benefits of clonal dwarfing rootstocks
Dwarf trees need less water in a dry climate, less fertiliser in a world of scarcity, take up less space in a smaller yard, have a lighter impact on surrounding plants, are easier to protect with netting, are safer to maintain and pick, produce more fruit per square metre (trials show nearly 50 tonne per ha is achievable within 2 years of planting, ie 5kg per square metre!), produce fruit much quicker than seedling rootstocks and allow more varieties to be planted in a given space.
*Plant growth is always influenced by climate, nutrition, water availability, etc, so height figures are always only a guide.