Knowledgebase

Antifungal soil drench for exterior beds? #741749

Asked March 31, 2021, 11:49 AM EDT

I am looking for a recommendation for an antifungal product that we can use as a soil drench in our exterior beds, as well as recommendations for topical treatments. We did a landscaping project last spring, and had widespread die-off (either blooms that rapidly turned brown or complete death of the plant) of perennials, such as phlox, catmint, and shasta daisies, which appeared to be from various fungal infections. We had similar issues with shrubs such as dwarf gardenias and a small specimen of a red-twig dogwood. And this year, we had almost immediate browning and die-off of the blossoms on one of our camellia bushes. I do not believe that it is any kind of frostbite, because another camellia of the same variety on the opposite (north) side of our house is doing just fine. I'm attaching photos of the affected camellia. I believe the fungi were introduced in the mulch, which sprouted mushrooms throughout the summer whenever there was extended rainy weather. So I think we have a widespread problem that needs to be attacked in the soil rather than just above ground. I'd appreciate any recommendations you can provide about how to control this problem, both soil drenches and topical treatments.

Prince George's County Maryland

Expert Response

The fungi you see on mulch grow only on dead organic material, which is what mulch is. They decompose.  They would not get on live plants, so there is no connection between the mulch fungi and your plant problems. 

Our plant pathologist looked at the camellia photos.  It is not a disease (fungus) causing the browning.  Looks like cold damage.  Camellias are very susceptible to cold temperatures, some varieties much more than others. This can explain the difference between your camellias.  Prune off the damaged blossoms. A camellia on the north side of a house has a very different environment than on another side, also.  This can account for the difference between your two camellias, too. 

Each species of plant has diseases and pests that are specific to that species. So, when you see a lot of problems across many species, it is usually a cultural/environmental situation causing the problems, not a disease or pest.  

Please send us photos this growing season of any problems you see as soon as they appear. 

Keep in mind that new plantings need about 1" of water a week. Rainfall should be supplemented if necessary during the growing season--spring through fall--for at least the first 2 years.  However, water should be applied at the base of the plant.  Do not keep wetting the leaves when you water--this can lead to fungal disease.    

In addition, mulch should be no more than 2-3" deep and NOT touch the base of the plants.  Keep it back a few inches from the trunks or stems.  It can encourage disease and pest problems. 

Ellen

Ellen Replied April 01, 2021, 9:54 AM EDT

Loading ...