young, 9 month old plant, center
Silver mound artemesia on left
An agastache on the right
My most recent favorite plant family is the Sedum/Stonecrop species. There are hundreds of plants in the sedum family from tiny pearl like matted groundcovers to tall erect almost bush like. These plants are hardy, drought tolerant once established, semi-deer proof and super easy to grow.
The varieties are near endless from deep dark purple leaves and stems to chartreuse. Blooms from Spring to fall. Flowers ranging from yellow, pink and purple-ish. I am still discovering new, hybrid varieties every year.
dramatic "black" variety
My all time favorite is "Autumn Joy" it's tall stems with mauve edged green leaves and mauve stems topped with dusty mauve flowers in late summer. An architecturally interesting perennial all year long. Even attractive in the winter as the dome shaped flower heads are very sturdy when dried by the sun.
Clumping growth habit, easy to divide.
The succulent leaves add interest and combine well paired with just about anything. It's currently in my front border with Bearded Iris, Daylilies, Silver Mound Artemesia, and Thyme. All of my plantings are less than a year old since we just moved in late August 2010. All Hess plants were in small 4" pots. They are fast growers even in Colorado.
I am not a professional, these a just my opinions. What works for me, may not work for you.
Easy to grow if you dig a hole bigger than the pot, add a handful or two of some compost. Fill the hole with water, put the plant in and backfill around the plant with the original soil mixed with a couple more handfuls of compost. Water it every day for the first two weeks, then about three times amweek the first year to establish the roots.
4-8 hours of sun or more and water regularly (2-3 times a week) should be all you need to grow successful plants.