Plant Encyclopedias. There are thousands of varieties of plants from all around the world that will grow and thrive in climates similar to your own.
A good point to remember: If a plant variety grows at the same latitude, altitude, and climate as your own anywhere else in the world, there's a good chance that it will thrive in your garden as well.
So in order to give your gardening or landscaping skills a boost, find out what your planting options are.
There are hundreds of plant encyclopedias to choose from. And basically most of them have good information. However, many cover the same information and won't be exactly what you need. As far as online plant encyclopedias and databases go, you can find out at least something about almost any plant. However, sometimes a lot of vital information gets left out.
So along with online plant encyclopedias and the information you can find online, you need a good general reference tool that will cover most everything.
I depend a lot on plant encyclopedias for ideas, plant knowledge, and design skills. And actually, my design skills have increased proportionately with my knowledge of plants.
Top of the shelf:
Flora: A Gardener's Encyclopedia is the absolute best plant reference I own. I say that because it's the one I use the most. It covers more than 20,000 plants on 1500 pages. And most are illustrated with pictures.
The book serves me as much more than just a picture reference though. Each plant has details on growing habits, propagating, and more.
The National Garden Book is a reference that I recommend everyone own in addition to any other plant encyclopedias in the library. It's a must for beginners.
American Horticultural Society A to Z Encyclopedia of Garden Plants
This is another large book of 1092 pages. Being a picture person, this one appeals to me because I have 6000 pictures of plants to look through. It covers a total of 15,000 plants.
The A-Z Encyclopedia of Garden Plants also has sections on growing tips, background information, and basic gardening techniques.
Just last week I added anther good one to my collection of plant encyclopedias. American Horticultural Society Encyclopedia of Plants and Flowers, The (American Horticultural Society Practical Guides) is a little different because it has detailed information for finding the right plant for the right garden location. This is a big plus for do it yourselfers. I'm very impressed with what new stuff I'm actually learning from this one.
Remember, the right plant encyclopedias will introduce you to new varieties allowing you to be more adventurous and creative in your gardening deeds.
Specific Plant Encyclopedias
Specific plant encyclopedias focus on one particular type or style of gardening (Perennials, shade, desert, etc.). Many gardeners find these to be handy and easier to use for individual problems and projects.
The following list isn't of all the encyclopedias I own. These are just the ones that have been most helpful in my own landscape and gardening education.
Taylor's Guide to Annuals
The Illustrated Encyclopedia of Cacti
Rock Garden Plants: A Color Encyclopedia
American Rose Society Encyclopedia of Roses
Rodale's Illustrated Encyclopedia of Perennials
An Encyclopedia of Shade Perennials
National Audubon Society Field Guide to North American Wild flowers: Eastern Region
National Audubon Society Field Guide to North American Wild flowers: Western Region
Regional Gardening References
Regional gardening references not only cover plants that are unique to the different climate zones, but generally also deal with gardening techniques, methods, and information that is specific to each zone. For a look of some of the more popular regional references.
Native Plant Encyclopedias
One of the best native plant encyclopedias that covers plants from all regions is actually online and free.