Site analysis is the process of determining what is present at the site and examining the natural elements and conditions that affect the site. Ideally, this process would be undertaken for a whole year so you can observe the site during each season. You can shortcut this process by asking knowledgeable gardeners about local conditions in general or your site specifically. The better you understand your land, the more successful you'll be in creating a successful landscape.
Weather plays a major role in all our gardening activities. It guides our selection of plants, determines the length of our growing season, and impacts the upkeep of the garden. Information on the average rainfall and the average freeze dates in the spring and fall should be obtained. This will tell you how long your growing season is. This data is usually available from the Cooperative Extension Service in every county. Also, ask what the USDA hardiness zone is for your area. Be aware that the hardiness zone for your particular site may vary somewhat from that of the area as a whole.
When it comes to garden design it is important to know how much sun hits your site.
Solar Aspect means how much sun hits your site. Are you on a hill facing north or south? Does your site receive full sun all day or is it shady part of the day? And which part of the day, morning or afternoon, does your site have shade?
Wind Patterns means which direction does the wind typically blow in from? There may be seasonal differences between winter and summer winds. Structures, windbreaks, trees, or plantings can have an impact on wind patterns.
Topography refers to the three dimensional aspect of your site. Is the site totally flat or are there hills and gullies? If your land has moderate to steep topography, you may need to be concerned about erosion. During a rainfall, where will the water drain as it comes off your roof and other hard surfaces? You want to keep water away from the foundation of your home, but it is desirable to put this excess water to use in your garden areas.
Microclimates are the small areas in your yard that have a different climate than the rest of the site. A flowerbed against a south-facing wall will have a warmer climate than a bed out in the open. A flower bed placed under a downspout will be wetter than most parts of your yard. You can use microclimates to place plants to their best advantage. For example, if your site is in USDA winter hardiness zone 5, you could probably use some zone 6 plants along a south-facing wall.
Existing Hardscape includes things like patios, retaining walls, drives and sidewalks, or any type of structure. It's an element that is normally considered permanent and is often fairly expensive to put in (or remove). Your new home very likely already has some hardscape in the form of a driveway and sidewalk to the front door. Consider very carefully where you might put any additional hardscaping.
Character of the Neighborhood
Character of the Neighborhood often determines the type of existing landscapes. You don't need to copy them, but you should be cognizant of what will be compatible with your neighbors. This is particularly true if your home is in a development where the lots are small and are not enclosed with fences or walls. Also check on any landscaping covenants that might be applicable.
Existing Plant Inventory
Existing Plant Inventory means seeing what's already there. On small lots in developments there is often nothing, or at least weeds you don't want. Also, observe what native or adapted plants grow well in neighboring yards. If you are not sure about the identification, ask a local gardener.
Soil is what makes a garden successful. It's a good idea to have your soil tested. Again, this is something the Cooperative Extension Service can help with. Once you know what kind of soil you have then you can add the appropriate soil amendments.
You will need to know what kind of structure your soil has, whether it is clay, sand, loam or a combination. The soil structure has a great influence on how your soil drains or holds water.
This tells you if your soil is alkaline or acidic. Some plants won't grow in soils that are too acidic or too alkaline. The pH is measured on a scale of 1 to 14 with 7 being a fairly neutral soil. Productive soils have a typical range of 5 to 8. Soils with a pH above 8 are very alkaline and below 5 very acidic.
Soil can be tested for fertility to determine the available nitrogen, phosphorous, and potassium (NPK, the numbers you see on packages of fertilizer). Another component of soil fertility is mineral content. Our soils may have enough minerals but they are sometimes not in a form available to plants.
Sounds like a lot to know, but going through the process of analyzing your site will help when you start your preliminary landscape design.