Monday, February 24, 2014

RIP Impatiens

I wrote on April 19, 2013 about impatiens mildew in my garden article "Impatient with Impatiens" #118 in the Galva News.  Looking down the right side of this blog to article label "Impatiens" and reread if you're an impatiens flower lover.  The information in this article still holds true.

And now the update:

Monica David of the University of Illinois Extension office told us the fungal disease is as bad as they had predicted.  Not only is it not contained or eliminated, it has decimated the impatiens industry.  We can no longer hope new plants won't be infected.

If no more impatiens are planted this summer in the US, this disease will still be in the soil for at least another five years.

Is your yard infected?  If you planted impatiens in the last 2-3 years and had the leaves and flowers fall off before the end of summer, the answer would be almost assuredly "yes."  Hopefully, you raked up all the plant debris and disposed by burning or in a trash bag.  Do not compost.  If you had this die back in pots of impatiens, you should have disposed of the potting soil in the same way.  Both of these suggestions will not have saved your soil from harboring the fungus, it may have prevented it from being spread.

This particular fungus can not be controlled or eliminated with the commercial or homemade products for mildew.  This is different than the fungus you battle on plants such as lilac, bee balm, phlox and etc.

If you did not plant impatiens in the last few years, do not plant them now.  There will be a few places that still carry them and you will be tempting the mildew fairy to bring in a long lasting fungal problem for your gardens.


  • Do not buy impatiens (New Guinea impatiens are not diseased and may be used.)
  • Keep impatiens out of your yard for the next 5-8 years.
  • Removed diseased plants.
  • Do not compost.
  • Use alternative plants.
I will add another warning:

This particular mildew is also hitting basil.  I know!  Basil is one of my favorite herbs of summer!  Blue Spice Blue and Blue Spice Phil are both mildew resistant varieties.

 If you experience gray-green, yellow or purple lesions on the upper leaf surface, white gray fuzzy mass of spores and hyphae on the underside of the leaf, the new grow dies first and defoliation, leaf drop and death of your basil plants, the U of I extension office would like you to put your entire plant & root system in a baggy and bring it into the office for testing.  In this way they will be able to tell where the fungus has spread.

And you ask:

Why do we see both of these plants (impatiens and basil) in stores this year and they look healthy?  Because the nursery where it was raised used powerful chemicals to keep it controlled (not eliminated but controlled.)  We, as gardeners, are not licensed to have these chemicals.  When these chemicals are no longer used after we bring the plant home and put it ever so artfully in the soil,  the fungus will again start growing.  I tell you this so you will realize seeing a healthy plant in your favorite garden store does not guarantee it will not be infected and die once it's planted at your home.

The bottom line:

Listen to mama:  do not buy impatiens (except New Guineas) and do not buy basil (except powdery mildew resistant varieties.)

Part of gardening is adapting to nature's twists and turns.  This is one big twist but at least it isn't about the horribly expensive tree you planted twenty years ago.  The truly sad part of this story is what it has done to the impatiens industry and if they can survive this disaster.

Ask your reputable nursery owner for impatiens substitutions.  They will have an enormous variety of shade loving plants that just might become your new favorites.  They will also have basil suggestions.  Reputable nurseries want you to have healthy plants - work with them - make them your new best friend.  Win~win.    

No comments:

Post a Comment