April

Welcome to the new monthly blog from Maryland Flower!  As you look outside you can see that spring has finally arrived.  We hope you are enjoying this beautiful sun shiny weather.

To begin our blog this month we are going to address some concerns that have come to our attention concerning downy mildew in impatiens.  Downy mildew is a fungus-like microorganism that has ravaging effects on impatiens in Maryland gardens.

This disease is not new and has been present in many different areas of the country.  Weather conditions seem to have a significant impact on its survival.  Over the last couple of years, Maryland has experienced milder winters with minimal freezing temperatures.  These conditions have allowed the downy mildew to over winter in the garden soil.  Moist, humid and warmer temperatures in the summer allow the fungus to thrive.  With the continual freezing temperatures of this past winter, it may have helped deter the spread of the mildew.  Unfortunately, this doesn’t guarantee that it has been eliminated.

The initial symptom of the disease will appear as a light green (almost yellowing) or mottling on the leaves which could eventually cause them to curl downward.  The underside of the leaves may also have white fuzzy mildew.  With progression, the plant will fail to thrive, causing the leaves to eventually fall off and the stem will turn brown and soft.

We are trying to help lessen the spread of this disease by treating our seedlings with fungicides. However, once you detect any signs, changing the location of the impatiens and disposing of them into the garbage can be very effective.  Do not allow the plant or any of its parts to remain as this could lead to the spread of the fungus to surrounding plants.  We would recommend using containers or window boxes for plantings.  Planting the impatiens 18″ apart will increase the air flow between plants. Also, the best time to water is in the morning allowing enough time for the plants to dry off before evening.

Some good alternatives to impatiens are New Guinea impatiens, Coleus, Begonias, Vinca, Torenia and Hypoestes (polka dot plant).

This is not the end of impatiens in our gardens. They have been and will continue to be extremely popular.  Mother Nature is at work here and we will all see this through!

 

 

For further information, please view the University of Maryland website at ipmnet.umd.edu