Question
My last two rounds of annuals (zinnias, then mums) took off beautifully and then, a few weeks after I plant them, the flowers start to look ashen and then the plants start to die.  When I pull them out of the ground, there is no root system.  I think my dog is peeing in the flower bed and that this is what is killing them.  Short of getting rid of the dog, is there anything you can recommend to solve this?  Any flowers that wouldn't be so vulnerable to this problem?

Answer
Lynn, I wish I had a better answer, but there are no flowers or vegetable plants resistant to dog and cat urine.  The ammonia in the urine is deadly to plants, especially young seedlings.

There are several animal repellants on the market such as Deer-Off.  The smell is offensive to mammals and will cause them to look elsewhere.  Some gardeners use cayenne pepper.  But the only sure way to protect the plants is to somehow keep the dog away from the garden bed.

Some natural deterrent plants include herbs and marigolds.  Once again, the smell is offensive to most animals, but it is one of those remedies that works in about 50% of the cases.  It is still worth a try.

I would be remiss if I didn't mention that there is another possible factor causing the roots to stunt.  Root-rot is a common fungus disease that invades many North American gardens.  Once in the soil, the only way to eradicate it is with solarization.  This is accomplished by laying black plastic over the area for three months.  The sun will then bake the soil, which in turns kills the disease.  

The only way to know if this is your problem is by taking a soil test.  Most garden centers sell soil test kits, and many nurseries will test your soil for a nominal fee.  Just take a sample from near where the plants are dying and place it in a paper bag.  If your garden center does not do tests, they can definitely recommend someone in your area who does, such as your local county extension office.

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

Regards,

Mike