Growing perennial plants successfully requires some knowledge about a plant's specific cultural requirements, much of which you can find in our catalog entries. But there are also some very basic things to consider about your site. These include exposure, climate, soil type, drainage, pH and nutrient availability, and water availability.
Exposure, or availability of sunlight, is a major consideration for most plants. Determine whether your site has full sun (at least 6-8 hours of direct sun a day), partial sun/partial shade (4-6 hours of direct sun preferably earlier in the day), dappled or light shade (intermittent shade throughout the day and fewer than 4 hours of direct sun) or full shade (less than 2 hours of direct sun either very early in the morning or late in the day).
Climate includes temperature averages and extremes, humidity levels, general precipitation amounts and so forth. Using the USDA Zone maps will help to determine the typical temeprature extremes for your area, but they do not incorporate information such as humidity and rainfall. In other words, Zone 7 in Virginia is not the same as Zone 7 in California. If you are new to an area, contact your local Cooperative Extension Service for more information about local conditions.
Soil type and Drainage are usually closely linked. Soil type can range from loose and sandy to heavy clay and anywhere in between. Sandy soils tend to drain well, but hold nutrients poorly. Most plants will fare better in these soils if you add adequate organic matter, such as compost, which will help the soil hold moisture and nutrients, and use slow release fertilizers so the nutrients stay in the soil longer. Heavier clay soils often drain poorly, but are likely to hold nutrients better. Adding organic matter, (again compost is the first choice), will help to improve the drainage of these soils so there is more oxygen available to plant roots and the soil will be less apt to become compacted and brick-like.
Nutrient availabilityand pH are dependent on soil type, the amount and type of organic matter in the soil and whether fertilizers and/or lime are added to the soil. The best way to determine these values is by testing the soil where you plan to grow your perennial plants. Check with your local garden center or Cooperative Extension Office for more information on how and where to have your soil tested. Your soil can often be amended to better suit the needs of the plant(s) you choose.
Water availability is a factor of climate, weather, location, water supplies and access to irrigation. Climate and weather are obvious, but location can play a large factor as well. Planting areas under large, moisture-hungry trees, below wide overhanging eaves, near downspouts and so forth will require extra consideration when choosing and maintaining your plants. Plants that require a significant amount of moisture may require regular irrigation on some sites, others that prefer a drier soil may suffer if there is excess irrigation or inadequate drainage. The cost and availability of supplemental water, where needed, should always be considered.
Your local garden centers, books, magazines, websites, botanical gardens and so forth are usually good sources for more information about these factors.