Answer: It's best to begin landscaping with an overall plan for what you are going to do, such as foundation planting here, sitting area here, flower garden here.
Then you would select specific plants based on the growing conditions where they will be planted. For instance, if is is shady or sunny and at what time of day, if the soil is wet or dry, what kind of soil it is, and how much space the plants have to grow and mature over time.
I would suggest you make a rough sketch drawing of the area you want to plant, take down the dimensions of the planting area, check the compass to know where north is, and possibly take a photo or two of that area of your yard. Bring these with you to consult with a nurseryman, or work with a garden designer or landscape architect to begin planning and decide which plants would do well in that spot.
You might also take a look at a book or two on gardening, the Dummies series includes several excellent choices. These books are straightforward and very practical and should be very helpful. You should be able to find them at the library or bookstore. Enjoy your new landscape!
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