A wide variety of dwarf and semi-dwarf fruit and nut trees are available which are ideal for container gardens and more are developed each year. There are several factors to consider when deciding which trees to plant, including climate and microclimate, availability of a sunny location, pollination needs, and of course, your personal likes in fruit and nuts.

CLIMATE
The area where you live will have a general climate – how hot it usually is in the summer, the length of the days, how cold it is in the winter, humidity, rainfall, etc. Every variety of tree has a particular climate it prefers, and a range of temperatures and humidity in which it will grow and produce. Some trees, such a citrus, avocado, papaya and fig, prefer warmth year round and will tolerate little freezing weather, where others require varying periods of cold in the winter in order to flower and bear fruit. Trees requiring relatively warm winters, when grown in containers, can be grown in considerably colder regions than where they would normally survive, providing they are moved to a warm, protected area in the winter. You can even grow a lemon tree in North Dakota if you like, by making it an indoor tree for the cold months. If you do move a tree indoors, be sure to place it away from drafts and heating vents. And slowly introduce the tree to the lower light indoors and brighter light again outdoors by slowly acclimating it, an hour or so more each day, over the course of two to three weeks.
NOTE: A container tree will be more susceptible to hard freezes than one planted in the ground as its roots are more exposed. The soil in a container will freeze more readily and deeply than will the ground.

MICROCLIMATES
Your yard or deck will have variances in climate depending on exposure and surroundings. A north facing wooden deck with no protection will be much cooler than a south facing cement one surrounded by stucco walls on three sides. An east facing patio which gets only morning sun will be cooler than one facing west getting the warmer afternoon sun. A particularly windy location will be dryer than a calm area.
NOTE: Areas of strong wind should be avoided when choosing a location for your tree, as the wind can damage the fruit and tree.
If you would like to grow a tree which is rated for areas just hotter or just colder than where you live, you may still be able to raise a healthy and productive tree by making use of the microclimates in your garden.

CHILLING REQUIREMENTS
Several type of trees require prolonged times of cold in the winter in order to go fully dormant, and hence flower and produce fruit the next year. These include
Almonds Apples Apricots
Cherries Chestnut Figs
Filberts Peach Pear
Pecan Persimmon Pistachio
Plum Pomegranate Quince
Walnut

The length of cold needed, generally temperatures between 45 and 32 degrees F (7 and 0 degrees C), varies by variety. Some trees needs as little as 100 hours of chill temperatures, others require 1000 hours or more. Check the particular needs of the variety you would like to grow and compare against your normal winter temperatures to see if your tree will do well.

SUNLIGHT
Fruit and nut trees need sun to grow well and for the fruit to ripen properly. Determine how mush sunny space you have and determine how many and what size of trees you want in your garden. A dwarf tree will eventually need three to five feet in which to spread its branches, where a semi-dwarf would need as much as seven or eight feet. If you live in a particularly hot area, however, partial shade, especially in the hottest hours of the afternoon, may be necessary to prevent fruit sunburn and injury to the tree itself.

POLLINATION
Many types of fruit trees are self-pollinating, where some fruit trees and most nut trees require a second variety of tree for cross-pollination and fruit set. Some nurseries provide grafted trees with two or more related tree types growing on the same trunk. This grafting can solve the pollination problem, or you can graft your own if you have very limited space.
Self-pollinating trees include:
Apricot
Avocado – though planting a second type will increase yield
Sour Cherry
Citrus
Fig
most Nectarine and Peach
Persimmon
Pomegranate

Trees that require a second variety for pollination:
Apple
Sweet Cherry
Pear
European Plum
Japanese Plum
most types of Nut
Note: Japanese and European plums will not pollinate each other due to bloom timing differences. You must plant at least two varieties of either European or Japanese plums for the best yield.

If you want a tree that requires a second type for pollination, choose varieties that bloom at the same time. Also, space the trees no further than 100 feet apart in your garden. Research your particular variety of tree to find the recommended pollinators, then choose one which will also produce fruit you like, perhaps a complimentary type. For example, if you want Fuji apples that are excellent for fresh eating, you can also grow a Granny Smith tree for its tart fruit that make excellent sauces and pies. Fuji and Granny Smith will pollinate each other well.

SELECTING YOUR TREE AT THE NURSERY
Younger trees are more resilient and transplant better than older ones, and will produce better in the long run. One year old trees are ideal for planting in containers. Most dwarf varieties will produce their first fruit in their second or third year, and semi-dwarf trees in their third to fifth year.

If the tree is container grown (not bare-root or balled-and-burlapped) check to be sure it is not root-bound. Gently remove it from its container. If the roots are tightly bound and wrapping several times around the inside of the pot, choose another tree. Being root bound will affect the tree’s health and slow its growth and production. Select a tree with good shape and balance, with a healthy root graft, and if leafed out, with good color to the leaves. Inspect for disease and insect infestations and choose a tree free from both.

Buy your tree from a good, reputable nursery. You want to be sure your tree has had good care and will remain healthy. And, should anything go wrong, a good nursery will be able help you diagnose and care for your tree, or replace it if needed.

Plant your tree as soon as you can in a well-draining soil and container. Give it plenty of water whenever the soil is dry to one or two inches, but be careful to not over water. Note that some varieties prefer more water than others.
After new growth begins you can fertilize sparingly, being careful not to give too much at any one time. A build-up of salts and excess fertilizer in your container can harm or kill your tree.

With good care, your tree will give you many years of beauty and joyful harvest.

Here are two on-line shops with a good selection of fruit trees for your garden: