First you need to study your area, is it sunny, shady, part sun/part shade? Check what time the sun hits the south area of your gardens, its usually around 12:00 pm thru 4:00 pm, the plants listed are a few I know to be hardy and you can't go wrong with them, they are not that expensive, the larger the plant the more expensive. You may want to buy just a small or medium size plant to try it for a season before investing in an expensive large plant that may die on you.
For the area that receives the south sun & southwest you need plants/shrubs that can take full sun.
Plants: Autumn Joy Sedum (grows about 18 inches with a spread 24 to 30 inches) Coneflower, Veronica, Columbine, Coral Bells, Lambs ear, Sedum ground cover, Hens and Chicks, Tiger Lilies, Forget me Nots, Chamomile, Gayfeather, Cushion Spurge, Obident Plant, Pinks, Adams Needle
North & East areas: Shade/some sun, Hosta's, Lenten Rose, Mrs. Moon Lungwort/Bethelem Sage, Sedum groundcover, Ajuga Bugleweed, Lily of the Valley, Vinca
Shrubs for Sun: Spirea's, Butterfly Bush, Forsythia, Lilacs, Azalea Cinquefoil
Shrubs for Part Sun Part Shade: Spirea, Hydrangea, Pee Gee Hydrangea, Goatsbeard, Deutzia, Kerria Japonica
Remember when you purchase small plants for full sun in small pots, at times it best to place them in part sun/part shade when they are small or young, as they grow/mature transfer to full sun.
After perennials are done blooming as each has it season, spring, summer & fall, what you can do is use annual filler plants, Ex: Petunia's, they like full sun, Impatiens like part sun part shade, Marigolds full sun, Zinnia's full sun
For walkways full sun: Spirea Shrub, Cinquefoil, Autumn Joy Sedum, Veronica and Lambs ear, Coral Bells, around the edges plant ground covers, Spirea's can be cut back and divided when they get to large.
Ex: Sedums, Bishops Weed (these spread quickly and can be divided)
For walkways with shade: Hosta's, Bethlehem Sage "Mrs Moon", Vinca, Ajuga Bugleweed, Lily of the Valley, Hydrangea shrub, Sedum groundcovers
For walkways part sun/part shade: Spirea Shrub, Hosta's, Ajuga Bugleweed, Bethlehem Sage "Mrs Moon". Spirea shrubs can always be cut back or divided when they get too large.
Always know your planting zone when purchasing plants and also the type of soil you are going to plant in.
If you don't want to be watering plants every day stick with shrubs such as Spireas, Cinquefoil shrubs or Autumn Joy Sedum which grows about 18 inches with a spread of 16-18 inches, this plant can be divided also. You can also use Sedum ground covers, the Sedum groundcovers come in a variety of colors and flowers or Cushion Spurge.
When planting an area its best to take some time and think about it, don't rush out and buy something, it may not grow and you will waste your money and end up buying more plants, plants are expensive. Give some of the ebay plant sellers a try, buy a few different varieties, see if the seller will combine shipping, most do, I purchased a Japonica shrub about 4 years ago and its doing great also an Arkansas Amsonia a slow grower but worth the price. Check prices on the web.
Something to think about is color, Veronica (the purple variety) goes well with yellow and pink yarrows or lambs ear (lambs ear's will multiply fast), Deep purple Coral Bells go well with the reds, whites & yellows. Dusty miller an annual looks well blended with purple and red plants.
When I was in Las Vegas I looked at all the plants that were growing in front of Caesars Palace one year, some were annuals, what caught my eye was Dusty Miller, they had placed Dusty Miller with Red Geraniums and Red Petunia's it was a sight to behold. You could do the same with Deep purple petunia's and Dusty Miller among your perennials. Now you may not like Dusty Miller but Dusty will put on a show when blended with other plants.
Remember to dig the hole twice the size of your plant and twice the size of a potted plant, give the plant some time before using a fertilizer, put some space between your plants, some perennial seeds may not come up until the following year, make sure you mark where you planted them, using a painted rock or good garden marker, you will forget what you planted :). If your plant does not seem like its doing too well after a week or two or its looking bad, move it to another area ex: part sun/part shade or to a moister or dryer soil and so on try that before giving up on a plant.
I can suggest the book "Flower Power" by Jerry Baker and any of his books, they are easy to understand and have humor, there are also recipes in his books to give your plants a boost with items you already have at home, you don't need to spend your money on expensive fertilizers when you can make them yourself also recipes to ward off the bugs, pests, white mildew on plants and a ton of other hints.
Please vote if this has been helpful.
Thanks for reading!