Plasmopara obducens. The symptoms are; yellow or stippled leaves, leaves that curl downward, white downy growth on the undersides of the leaves, leaf and flower drop and total plant collapse. They may be infected before you bring them home and develop once they have been planted.
There are many alternatives. SunPatiens for one. They are not affected by the disease. They are easy to grow and spread more widely than the regular impatiens. Then there are the begonias. The waxleaf has small flowers in pink, red and white. Tuberous have a much larger flower and in more colors. Then there is the Dragon Wing. They have a beautiful arching form. Rex has large and often, multicolored leaves.
Coleus come in multiple colors, leaf shapes and sizes. Some will even do well in full sun. A new series is ColorBlaze. They are purported to either bloom late or not at all. With the others, cut the blooms off as soon as you can as the plants tend to go downhill after blooming.
Another plant with colorful leaves is the caladium. It can be pink, red, white, green or a combination of them.
If you need trailing plants, think fuchsia. It, too, comes in many color combinations. There is also a dwarf bedding type. The only drawback to the trailing type of fuchsia is their tendency to break off in a strong wind. The hanging begonias also have this weakness.
Looking for blue? Wishbone flower (Torenia) is a blue/purple front of the border flower that will grow in shade. Nicotiana or flowering tobacco is another flowering annual to consider for your dark spaces.
There are always house plants that like shade. Wandering Jew, croton, Dracaena, philodendron and Chinese evergreen, for instance. Of course, all your house plants love a summer vacation outside in the dense shade. Why not use them for shade accent. Leave them in the pots (bury the pots or conceal them with bedding plants.) Two birds with one pot!
If you are looking for perennials, the others were all annuals, there are more choices than hostas. Coral bells (Heuchera) have a wide range of leaf colors from greens, browns, pinks, speckled and shades of gold. Wegiela is a small shrub that has pink or red blooms. Get adventurous. Put some color in those dark spaces.
If you would like more individual help, call the Extension Office at 218-998-8760 or stop in (505 South Court St). Or you can call the radio station – 1250AM – each Saturday morning or stop by the City Café & Bakery, Fergus Falls, following the radio program.