Got spots? After this rainy spring we are seeing a lot of leafspot fungi infections on garden plants; practically speaking, there isn’t much we can do about them.
Not talking beauty marks, like the cheek freckle on Kitty Russell, the saloon owner in Gunsmoke TV series, or naturally occurring blotches on popular house and garden plants. Not the spots caused by herbicide or insecticide drift, or those left by sucking-type insects, or circles in the lawn, or the harmless but alarming way gardenias and magnolia leaves naturally turn yellow before they shed.
This is about leafspot fungi, which are so common in our rainy, humid climate it is hard to grow roses, hydrangeas, zinnias, maples, tomatoes, red-tip photinia, India hawthorn, magnolias, hollyhocks, and many other popular garden beauties without them. Unlike fungi that grow in threadlike mycelia mats and make mushrooms, leaf spot fungi make spots on leaves from which tiny spores easily blow or splash to other plants. Some can be carried for miles in strong windy weather; you can plant a tomato or rose on top of the state capitol eagle, and it will still get leaf diseases.
At worst, highly susceptible plants can be completely defoliated and die; at best there is just a little discoloration which most folks rarely even notice and can be ignored by all but the fussiest - I mean fastidious - gardeners. In many cases where there is little control and it doesn’t actually kill plants, I simply accept them as natural phases of some plants; call it a “spotted-leaf maple” and let it go.
Truth is practical controls are iffy for most gardeners. Though cultivars of normally-devasted plants, like modern tomato varieties and certain old-garden roses, are naturally resistant to fungal infections, even they can get a little touch in our acid-test climate. If you aren’t already stuck with the susceptible kinds, look for disease- resistant cultivars or other plants entirely. This means avoiding planting many hybrid tea roses and heirloom tomatoes which are predictably hard hit. This information is easily found online or through local garden chat groups.
Second line of defense is not planting disease-ridden plants close together; spread them out for better air circulation and faster leaf drying, or interplant with other species rather than all one kind in a row. A mixed garden usually has fewer problems with insects and diseases.
Then comes sanitation - as leaf spots appear, remove the worst-infected leaves as best you can, rake up fallen infected leaves, prune heavily damaged plants to stimulate strong healthy new growth, and lay fresh mulch to reduce spore splashing. And try to water the soil, not the leaves (I know, “rain happens), early in the day so leaves can dry before dark.
Finally, the fungicide thing. Most fungicides don’t outright kill fungi; they are protective films, like sunscreen, best applied before infection. And they are never a one-shot thing - they usually last a couple of weeks or rains before needing to be reapplied, and new leaves need protection. So, they are iffy for all but the most dedicated gardeners.
And no, home remedies do not work reliably. I am so very sure of this! And not all are safe to use on edible plants. And, unlike pharmacists, not all garden center staff have deep training in plant diagnostics, so always read labels before buying or using fungicides. Just like choosing medicines, select specific fungicides for specific problems on specific plants. Use the MSUcares.com search box to learn what/how/when to treat garden diseases.
Otherwise, take off your glasses tolerate what you can. Rainy leafspot season is upon us.
Felder Rushing is a Mississippi author, columnist, and host of the “Gestalt Gardener” on MPB Think Radio. Email gardening questions to rushingfelder@yahoo.com.
