Friday, March 22, 2013

Rethink Impatiens for Your Shade Bed


If you have a shady spot in your yard where you usually plant impatiens, you may need to rethink your choice this year.  There is a new disease that is devastating to impatient plantings called downy mildew. 
Downy mildew is a fungal disease that cannot be controlled once your impatiens show symptoms.  If left in the bed, you wind up with nothing but green sticks.  In fact, the local growers are not even going to offer impatiens this year.  You may be able to find them in the big box stores, but I still would not recommend buying them. 

Bed of green sticks.

 Downy mildew shows up when the leaves yellow and curl.  If we have humid weather, you can flip the leaves over and see a white coating of the fungal spores.   Eventually, all the flowers and leaves will fall off, and all you can do is pull them up. 
Fungus on the underside of the leaves.
 
So, how does downy mildew get on them?  Well, unfortunately, more ways than one.  The fungal spores can be blown in on the winds of a thunderstorm.  After they are on your impatiens, the spores can be spread by water splash as you go around with the hose.  Replanting with new impatiens won’t work either, as researchers think that the spores may linger in the soil.  There is even talk that the disease may be seed borne, and the healthy looking plants at the big box stores may in actuality have the disease already. 

 The plant breeders are on the scene, working to make a selection that is resistant to this.  In the meantime, maybe try begonias for a change.