Question
I NORMALLY PLANT A BORDER OF 100 TO 125 IMPATIENS PLANTS IN THE FRONT OF MY HOME, FOR THE PAST THREE YEARS THEY HAVE DEVELOPED NECROTIC SPOT VIRUS. IT STARTS IN THE SAME AREA EVERY YEAR AND SPREADS TO THE REST OF THE PLANTS. I ALSO HAVE "PACHYSANDRA" BEHIND THE IMPATIENS.  A FEW BLACK EYED SUSAN ARE ALSO GROWING. I WOULD LIKE TO KNOW WHAT I CAN DO TO AVOID THIS NEXT GROWING SEASON. I LIVE IN NORTHWEST PENNSYLVANIA.  ANY HELP YOU CAN GIVE ME WILL BE GREATLY APPRECIATED.

Answer
Chris, the best thing you could do is solarize the soil. Based on your description, the necrotic virus is a soilborne disease. It will live in the soil until eradicated. The best way to do so is to cover the area with black plastic for 3 months. It is most effective if done during warm weather. This will kill the disease and allow you plant the impatiens there again next year.

One other possibility is that the variety you are growing is extremely susceptible to this particular disease. You may want to try another variety next year. The following websites will give you several ideas for hybrid impatiens.

http://www.parkseed.com/ (Just type impatiens in their search field)

http://www.burpee.com/category/annual+flowers/impatiens.do

http://gardeners.harrisseeds.com/cart/browse.asp?subcat=126

You can also spray the plants every 10 days once they start blooming next spring with a copper-based fungicide. I personally use Soap-Shield, which can be purchased through the following link:

http://www.gardensalive.com/product.asp?pn=8066&ss=Soap%20Shield

I hope this information helps. Please write again if I can ever be of assistance.

Regards,

Mike