The Right Site
Light - All types of rosemary grow best in sunny or slightly shady locations where they can receive at least 4 to 5 hours of sun a day.
Soil - They insist on soil on the dry side, so it must drain well. It should be neutral or slightly alkaline (pH of 6.8 or above). Soil pH influences the availability of various nutrients to plants. Test your soil with a soil test kit. If it is very acidic, add wood ashes, lime, crushed eggshells or sea shells to it every 2 to 3 years.
Planting Seedlings - Space prostrate or other small rosemary transplants from the nursery 18 to 24 inches apart; space larger plants in containers 24 to 36 inches apart. Plant shrub types in 2 or 3 gallon pots 3 feet apart. Follow these steps:
Make sure that all danger of frost is past and the soil is warm and dry. Loosen it down about 8 inches with a trowel or shovel or spade and remove stones and debris. Mix in some general purpose slow-acting granular fertilizer and smooth the planting area.
Plant on an overcast day or late in the day to spare young seedlings from sun stress as they adapt to the outdoors. Dig holes in the planting bed about the size of the containers the seedlings are already growing in.
Tip each seedling into your hand while tapping on the bottom of the pot. Set one in each hole and firm the soil over its rootball and around its stem to support it.
Water immediately. If you have added granular fertilizer to the soil, do not feed the plants further at this time. However, adding some plant tonic to the water helps ease transplant shock for seedlings. This step is optional.