Dwarf trees are produced by grafting a standard variety tree onto specialized root stock. Dwarf trees need good soil conditions to help them resist disease.

Here are some guidelines:

• check they are ok more often than regular sized fruit
  trees
• add plenty of organic matter to the soil mix as you plant them
• make sure they have good drainage before planting
• They need full sunlight. Don’t plant them under an existing shade tree.
• Dwarfed trees may not live as long. They mature faster and grow old
  sooner, yet with proper management, you can extend those years.
• Those with heavy produce, such as apples and peaches, may need some support
  
  General organic guidelines for fruit trees are:
  
  Keep a thick layer of compost around fruit trees and bushes, extending out to the drip line, the perimeter of the plant. Feed with an organic fertiliser, ie seaweed. Do not lay compost, etc hard against the trunk (this encourages insect attack and rot.
  
  Mango: likes deep fertile soils and good drainage. small trees are easily
  killed by frost.
  Avocado: plant them in deep, well drained, light, acid (pH6-6.5) soil rich
  in humus. protect from strong winds and frost.
  
  For general info on dwarf trees, see:
  
  How to Dwarf a Tree
  
  Pot a Fruit Tree