Question
We live on the edge of a lake & have many built-in flower boxes on our 3 levels of deck. Our house is sage green w/white trim.  I love the way our boxes look w/multi colors of impatiens.  Any ideas on other annuals to try or perennials I might mix in & then complement w/bright annuals?  Most of the boxes are on the N side of the house so they  get brief direct morning sun and then indirect sun/shade the rest of the day.

Answer
Kim,
Lucky you to live on a lake! As you know, the north side of any house is shady enough to limit the plant selection that will do well, so it's good that you like impatiens.  

Window boxes aren't good places for perennials because they get a lot colder than the ground temperatures, so the roots are damaged or killed in the winter.  Also, you should be changing the soil in your boxes every other year in order to have the best growing conditions so that your annuals will thrive.  (I usually put my old soil around shrubs and trees, or in the veggie garden)

As you know, impatiens get pretty big as the season goes on, so any small plants would be overwhelmed by them.  But you can use plants that will hold their own such as Coleus (colorful foliage) or the larger ferns sold as perennials (plant them in the garden in the fall) or ferns sold as houseplants.  

Speaking of houseplants, the variegated Spider plant makes a great window box container in shade - the long stems with the tiny spider plants at the end hang over the edge of the box, and it does well in shade.  Variegated ivy is good too.  

I hope this helps!
C.L.
www.gardenlady.com