Ask Mr. Smarty Plants

 This Mr Smarty Plants is pleased to see a question from his old home country!   I have fond memories of the deep pine forests.  Thinking of that, though, reminds me that this is a tough question!  The natural areas near my home had a layer of pine needles, maybe some grasses and very light underbrush.  Let see what the Wildflower Center resources suggests for this situation.

Here are a couple previous answers that deal with the issue of trying to grow under pine trees:

Flower color under large pine tree from South Elgin IL      Brings up possible issues of alleopathy, this is a natural effect where the tree and the debris from the tree tends to suppress other plants.  A review of information on your pines [see the technique in the message] will let you know if this exists with your pine stand.

Flowers under pine trees from Elkhart Indiana 
So, we will use the same method detailed in the previous answers to find flowers that will grow in part shade, tolerate acidic soils and are native not only to North America but also to the area where they are to be grown

  The plants recommended for Idaho are published by the Wildflower Center as the Idaho Recommended Species.   I then sorted the list for herbs and shrubs which prefer shade and acidic soils.  This gives the following list of suggested species [I’ve noted whether they need moist or dry soil].  You may want to read about each plant with your location in mind; I would trust that some of these should work for you.

Actaea rubra (Red baneberry)    Habitat:  Rich, moist, deciduous & coniferous woods & thickets
Aquilegia coerulea (Colorado blue columbine)
Campanula rotundifolia (Bluebell bellflower) - dry
Arctostaphylos uva-ursi (Kinnikinnick)
Rudbeckia hirta (Black-eyed susan) – dry or moist
Rudbeckia laciniata (Cutleaf coneflower) – moist acid soil
Vaccinium uliginosum (Alpine blueberry) - wet
Lonicera involucrata (Twinberry honeysuckle) – moist to wet
Amelanchier alnifolia (Saskatoon serviceberry)
Rubus parviflorus (Thimbleberry) – dry or wet