For gardeners who have been cooped up indoors too long, ordering from a plant catalog is an act of liberation. But some basic information is needed before making your list.
Know your United States Department of Agriculture (USDA) plant hardiness zone. The zones in North America are based on average minimum temperatures. For example, plants listed as appropriate for Zone 6 can withstand winters from minus 10 to 0 degrees F. (Maps of the zone breakdown are found in most garden catalogs and books, and if the catalog was mailed, the zone is often printed above the recipient's address.)
Have your soil tested. It's helpful to know what type of soil is present: Is it acidic or is there a lot of organic matter? Ask your local nursery or soil-conservation office for a testing-site recommendation. Identify the soil composition. Is it generally rocky, sandy, heavy clay, lime, or good loam (a fertile soil consisting of moderate amounts of sand, silt, and clay)? Does it drain quickly after a rain or is the water standing in puddles? Catalogs often explain the soil conditions preferred by each plant.
Know the amount and kind of sunlight in your yard. Are parts of it in direct sunlight most of the day? Are there shady patches under trees or next to buildings?
Consider the average amount of rain. There's no need to memorize rainfall tables, but general knowledge about weather conditions is helpful.