When you shop for a guide to plants, how do you choose? That depends...

Unless you're looking for an encyclopedic plant reference, choosing a guide to plants requires that you narrow your focus, so that the information suits your purpose. Even encyclopedic references rarely cover all of the aspects of plant life and the detail of information won't serve a specialized search for knowledge. Obviously, a planting guide won't have detailed information on rose horticulture, while a plant guide on companion planting won't have much on garden design. Let's take a look at the various types of plant guides and the main purpose each type serves.

The garden design guide to plants is intended to cover information on the elements of layout, soil conditions, walkways, garden walls and landscaping techniques. This best of this type of guide serves as inspiration, while also apprising you of the pros and cons of different designs and regional considerations, such as drought prone areas and landscaping with native plants. Instead of offering pat solutions and layouts, this type of guide introduces you to a variety of styles, such as the formal English and Japanese styles, versus a cottage or wildflower garden.

By contrast, a field manual teaches you how to identify plants, with detailed information on every part of the plant, including color and size of leaves, distinguishing characteristics and seasonal changes, blooms and fruits. There are subsets of this type of guide to plants, which focus on particular types of plants, such as grasses, trees and flowers. This is a great help to the plant buff an nature walker.

If your interest is in growing roses, grafting fruit trees or creating hybrids, look for a horticultural guide to plants. Again, you'll find subsets of specialized horticultural information ranging from raising orchids to cultivating heirloom vegetables. A horticultural guide gets you on your way to expertise in cultivating specific species and plant groups.

Medicinal plant guides make for fascinating reading and education in plants which offer remedies to human and animal conditions. Like a field manual, this type of guide gives detailed information on the physical characteristics, growth habits, flower and fruits, although a bit less extensively. The main focus is on how the plant may be used as a medicine, which parts of the plant are used and how it is prepared.

Books on companion planting teach you how specific plants prosper or fail as neighbors, as well as listing plants which serve to deter predators, or attract beneficial insects, birds and bees. For example, squill as an edging in the vegetable garden deters moles and gophers, while gladiolas planted within 100 feet of your tomatoes spells tomato disaster.

A general planting guide highlights seasonal considerations, usually categorized by growing zones.

Any guide to plants offers a wealth of information to the reader. Start with your subject of fascination. You may end up with a library that grows, along with your gardening interests.