I would like to plant a small garden for my wife
Gardening is the practice of growing and cultivating plants, sometimes referred to as horticulture.
Is there any limit to the types of plants that can be cultivated?
not at all! any plant cultivation is considered gardening, and it is also considered by many to be a relaxing activity.
Can i plant flowers and vegetables at the same time? 
Of course you can, people like to specialize though, some plants need special types of soil and fertilizers. It makes it harder to grow large number of different plants.
Is the history of the first garden recorded?
system, is the world's oldest form of gardening. Forest gardens originated in prehistoric times along jungle-clad river banks and in the wet foothills of monsoon regions. In the gradual process of families improving their immediate environment, useful tree and vine species were identified, protected and improved while undesirable species were eliminated. Eventually foreign species were also selected and incorporated into the gardens.
After the emergence of the first civilizations, wealthy individuals began to create gardens for aesthetic purposes. Ancient Egyptian tomb paintings from the New Kingdom (
Gardening
Gardening is the practice of growing and cultivating plants as part of horticulture. In gardens, ornamental plants are often grown for their flowers, foliage, or overall appearance; useful plants, such as root vegetables, leaf vegetables, fruits, and herbs, are grown for consumption, for use as dyes, or for medicinal or cosmetic use. Gardening is considered by many people to be a relaxing activity.
Gardening ranges in scale from fruit orchards, to long boulevard plantings with one or more different types of shrubs