How Should You Choose a Miniature or Dwarf Fruit Tree?
Miniature or Dwarf fruit trees produce regular sized fruit on smaller trees. A three to four foot high apple tree might produce up to 45 apples of a regular apple variety. A two foot high peach tree in a pot can produce 25 to 30 fresh peaches. Miniature trees are popular with backyard and balcony gardeners who want small amounts of several fruit varieties. Not all varieties of fruit are available as dwarf trees and the sizes are restricted by various means which cause certain types of trees to be better in particular growing situations.
The Four Main Ways to Reduce the Size of a Fruit Tree.
- Genetic Dwarf Fruit Trees
Some miniature fruit tree varieties are genetic dwarf trees, trees which have DNA that causes them to be very short with fairly heavy branches. These are not regular varieties made smaller, so you may not be able to get your favorite apple or peach variety as a genetic dwarf. These are most often peaches, nectarines, almonds, apricots and apples,small enough to grow in pots. Depending on your area, they may need winter protection.
- Dwarfing Rootstocks For Miniature Fruit Trees
Branches of varieties of fruit trees are often grafted onto dwarf rootstocks to produce smaller trees. Several varieties of dwarfing rootstock are available which restrict the tree's growth to various sizes. If you are choosing trees for a backyard orchard, you may want to grow several smaller trees of your favorite varieties, rather than one large tree with a few popular varieties grafted on.
Types of dwarfing rootstocks- Dwarfing rootstocks all have their own peculiarities. Some are suitable for particular varieties, but are too restrictive for other varieties. Some are resistant to drought and will grow on poor soils, others need high quality soil to produce fruit. The dwarfing rootstocks produce fruit trees that range from apple trees 3 to 4 feet high on M27 rootstock, but 6 to 8 feet high on M9 rootstock.
Dwarfing rootstocks are not the same across all fruit varieties. Although you can produce 3 to four foot high dwarf apples, a dwarf cherry is still a tree 18 to 20 feet tall. To grow a cherry tree you can cover with netting to keep the birds from eating the cherries, you are better to espalier the cherry tree against a building.
- Dwarf Rootstocks for Apples - the most common dwarfing rootstocks are the Malling rootstocks, developed at the Malling research station in England, or the Cornell-Geneva (CG) Rootstocks created at the Geneva Research station in New York. Rated most dwarfing to least dwarfing these rootstocks are available as M27, M9, M26. CG 11 is similar to M26 but has more resistance to some diseases. In some areas MM106 is also used, depending on the pests it must resist.
- Pears- in order from most to least dwarf, the common dwarfing rootstocks are Quince C, Quince A or EMH
- Dwarf Rootstocks for Plums, Damson Plums, Peaches and Nectarines - Plums, Peaches and Nectarines are dwarfed using the rootstocks Pixy or St Julien A
- Dwarf Rootstocks for Cherries - Cherries are most often dwarfed on Colt or Gisela 5 rootstocks. On Gisela 5 sweet cherries may grow to be 10-13 feet (6-8 meters) on Colt rootstocks sweet cherry height is 20 - 26 feet (3-4 meters). Sour (acid or "Pie" cherries) are less vigorous, growing 10-12 feet on Colt rootstocks.
- Dwarf Rootstocks for Apricots - Apricots can be dwarfed on St. Julien A or if potted up, Torinel.
How to Choose a Dwarfing Rootstock - Choose a dwarfing rootstock based on your soil as well as the size of tree you want. The rootstocks which produce the smallest trees M27 and M9 for apples, Pixy for plums and Quince C for pears, are only suitable for high quality loam soils with good fertility. Trees grown on these rootstocks have extremely restricted root growth and will need to be staked for their entire lives.
Less dwarfing rootstocks; M26 and MM106 for apples, Colt and Gisela 5 for cherries, Pixy for peaches, need staking for the first five years of life, but after that their roots should be able to support them.
Very low bush apples are easier to manage on highly dwarfing rootstocks such as M27 and M9. To grow an espalier, a fan or a cordon, you will need longer branches and a more vigorous tree.M26 or MM106 are better for these.
How Do You Tell Which Rootstock Is Used By Your Nursery? - All nurseries should be able to tell you what rootstock their dwarf fruit trees are grown on. Some specialist nurseries will graft the varieties you want, on suitable rootstocks for your purpose. If you want a heritage apple or a speciality apple on a rootstock for a cordon or espalier, ask a fruit nursery if they can supply you with a particular variety and rootstock combination best suited for your soil, and the type of pruning you want to do.
- Controlled Pruning To Produce Miniature Fruit Trees
Several methods of pruning produce fruit trees of a more manageable size. These trees may be on regular root stock, but are more often on a dwarf rootstock chosen to grow to a particular size. Espaliers, where the trees are grown flat on a set of wires on a building or between posts, or Cordons, where single straight branches are interwoven to create fence patterns are the two most common types of controlled pruning. Any variety can be espaliered or grown as a cordon which makes them useful for decorative fences or for growing flat against the protection of a wall. Cherry trees, often difficult to grow as dwarfs (a dwarf cherry may still be more than 20 feet tall) can be grown shorter if pruned against the wall as an espaliered cherry and are easier to protect from bird damage.
- Controlled Fruit Tree Growth in Pots / Root Pruning
Pot grown fruit trees, with restricted soil and root growth, can be dwarfed similar to the way a bonsai tree is dwarfed, with careful pruning of the roots and branches at the correct time of year. Many dwarf pot grown varieties are grown on dwarfing rootstocks to further restrict their size. These will require careful watering and feeding according to the rootstock used.
To Control Fruit Tree Growth in Pots. - Fruit trees can be grown in large pots (10 to 15 inches), except for cherries which need larger pots, up to 18 inches across. Fruit in pots should be grown in fertile soil with 1/3 of the soil mix being perlite or vermiculite to keep the soil from getting waterlogged. Fruit trees will require good fertility. You can use slow release fertilizer pellets, or feed them every two weeks with a high potassium liquid feeding (tomato fertilizers or another high potassium liquid. Fruit trees in pots should be re-potted every year or two after leaf fall. When your tree has reached it's mature size, it should be root pruned every other year and replaced back in it's pot with roughly 20% new soil. Root pruning for this purpose should remove at least the outer inch of roots. In years when the plant isn't being root pruned, you should mulch the soil well with organic material or add new compost to the top of the pot.