The worst you can do to your newly purchased plants is rushing ahead and planting them in the ground. Of course, you are keen to see those plants growing in your landscape but this enthusiasm could hurt your plants. Ideally you should prepare both the plants and the ground before you start the job.
Today, I am sharing some of the steps that I follow to transplant my plants into the landscape.
Planning the landscape
Whenever you want to plant trees in your landscape, first make sure that it is suitable for your climatic conditions. Also observer you landscape (garden, lawn etc.) and visualize how the plant would actually look like when it reaches it potential. Imagine how it would grow (some plants have columnar growth, some grow as woody shrubs, some are evergreen and some deciduous).
Imagine how your new plant would accompany others. Make sure that it does not intrude in to adjoining plants or is subdued by its neighbors. Every plant requires some ‘private space’ to grow healthy.

When to buy new plants for the landscape
Do not purchase plants until you are ready to transfer them in the ground. Keeping plants sitting in their containers for a long time could be bad for the plants, especially when you do not have proper space and required environment for those container-bound plants.
Select healthy plants from your nursery and make sure that they are already established in their containers (not transferred from the ground or another container). Also make sure that the plant is suitable for your climate, lighting and soil conditions.
The day before the job
Water the ground thoroughly the day before planting to make sure that the soil is a little damp. Also water the plant thoroughly to make the transplanting easy for you and the plant.
The best time to transplant is early morning or later afternoon. Do not transplant in the heat of the day, especially in summer.
How to transplant them in the ground
Dig a hole that is at least twice the size of the container of the plant. Add some rotted compost as base for the plant. Also add some organic fertilizer and cover it with a layer of soil. This would make a perfect mixture for the plant to establish and grow roots.
Take care while removing the plant from its container. Be gentle and avoid damaging roots of the plant. Some old container-bound plants are hard to remove from their containers and you might have to cut or break the container. Root-bound plants are hard to remove from their containers. Keep this point in mind when purchasing plants for your landscape.
After the plant has been positioned in its new place, fill the hole with soil and rotted compost. Do not pack the soil in hard neither keep it too lean to support the plant. Some plants might require additional support, provide them with stakes.
Lastly, water the plant and well and try to keep the soil moist until the plant has established itself in its new place.
Native plants do not usually resist transplanting, however exotic plant might be sensitive to transplant and not bear the shock. Make sure you understand all the requirements of such plants.