Tuesday, September 18, 2012

Downy Mildew On Impatiens Was A Real Downer


How'd those Impatiens work out for you in the garden this year?

What is left of my beautiful spotted Impatiens
If you were like me and many others in New England, your Impatiens were struck by a disease called Downy Mildew and they died a slow, ugly death.  Click the link below for a very comprehensive fact sheet on the disease, some images of plants suffering and what to do in the future.

Downy Mildew Fact Sheet

Downy Mildew has been around for a long time but seemed to work its way through the nurseries last year, and especially this year and the impact has been devastating.

The challenge with the disease is that the plants seem to yellow and the leaves curl, so you think the plants need water, which is exactly what they don't need.  Unfortunately, plants that are effected can not be saved by conventional fungicides.

The disease can overwinter in the leaves and soil, so clean up any remaining plants and remove the top layer in the garden where the plants were situated.  If you had Impatiens in pots, be sure to clean them up well before you put them away, or remove all the soil if your containers stay outside.

So what next?  It is recommended that you not replant impatiens in the garden were they were before, especially if they died from a Downy Mildew.  You can replant in containers, provided they were well cleaned from last season, that means the soil removed and the container(especially if porous) scrubbed.

The growing industry will certainly be on high alert next year for the disease and will be spraying and protecting plants as they grow, but I will be looking for suitable replacements.


Suitable Replacements 

New Guinea Impatiens are not effected by the disease, so they are a suitable replacement, even if they are not as soft and colorful, but they may be the best replacement for color in shade.

Torenia is a great plant for part sun to shade.  There is an upright and trailing variety and it comes in a range of colors but not quite like the Impatiens.  This can go into mostly shade and is a great trailer in hanging baskets.

Browallia is another good replacement with limited colors but a good performer all season in shade.

Alyssum has some nice colors and can give you that nice shot of color, but only to part shade.

There are so many Coleus to choose from in some wild colors, be sure to look carefully at the mature size since some 4inch containers of Coleus can grow several feet in a season.  A burnt orange and a lime green coleus are favorites for the bold color they add.  Tip pruning them several times during the year can keep them to any size.

Begonias can be great in the shade and containers and have lots of color choices.  The tuberous can be big flowerers, while many of the other varieties can have wonderful foliage.



1 comment:

  1. ARG! I never had heard that impatiens could get downy mildew. It has not been a problem here yet, and I hate to think of going without impatiens so I hope it never is.

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