The KPRC Radio Gardenline Tip By Randy Lemmon For 07-03-03 Printer-Friendly Version
Hibiscus - Yearly problems...
Randy is on vacation this week, but still wanted you to have a tip sheet from GardenLine, so he's re-running last year's Hibiscus Malady tip sheet. Have a great Fourth of July weekend, and Randy will be back with a fresh tip next week.
Yellowing leaves and premature bud drop on hibiscus are fairly normal problems at this time of the year. But which of two distinct reasons are causing these problems? Maybe more importantly the question is - should anything be done about it?
I say it depends on what's causing them. Normally, two things cause an inordinate amount of yellowing leaves and consequently bud drop on hibiscus during this time of the year. They are
1. Moisture extremes
2. Soil borne bacteria.
However, keep in mind that a few yellowing leaves, here and there, can be considered perfectly normal. A sudden rash of yellow leaves or a sudden rash of bud drop most often is related to MOISTURE EXTREMES. Here's what I mean: You may think you're keeping plenty of water on your hibiscus, but if it's not CONSISTENT, you will get the yellowing leaves/bud drop. It happens when our weather gets consistently above 95 degrees for our high temperatures. You may forget for two or three days to water the hibiscus and then you over water them, to make up for those missed days. MOISTURE EXTREMES-BOTH WAYS. Then, two days later you see yellow leaves or wonder why the buds yellow and drop off prematurely. Wonder no more!
If, on the other hand, you're convinced that you've been CONSISTENT with your watering practices, then an inordinate amount of yellowing leaves can mean a bit of bacteria/fungal disease in the soil. The real hibiscus professionals (with one of the local societies taught me that a simple treatment of Consan Triple Action 20 (1 ounce per gallon of water) on the soil only, takes care of what might be ailing the plant. If you cover too many of the green leaves with that Consan drench, you could get even more yellowing leaves, so make sure you apply it directly to the soil. (By the way, the two societies are The Lone Star Chapter and the Space City Chapter of the American Hibiscus Society.) http://www.lonestarahs.org/ visit here for more information about the Lone Star Chapter
A recent search for the Space City Chapter proved fruitless.
Temperature extremes have also been known to cause a flush of yellowing leaves on Hibiscus, but that's almost always related to Fall and Winter temperature fluctuations not our "always hot and humid" summers.
One final note, to ensure the health of a hibiscus, make sure you're feeing them at least once a month with a bona-fide hibiscus food.
Until next issue, here's to
Great Gardening from the GardenLine, heard
exclusively weekend mornings from 8 to noon
on Talkradio 950 KPRC.