From the August 2009 issue of The Petaloid, the official publication of the Lone Star Chapter of the American Hibiscus Society.
By Barry Schlueter
Making your hibiscus hobby easier
Houston is horribly hot this month. Working outside on hibiscus is tolerable only early in the day and late in the day. Is there anything that can be done to make hibiscus care and maintenance easier this time of year?
For starters, move your potted exotic hibiscus into shade. With current sun angle and intensity, it takes little or no direct sun to produce some flowering. Your care and maintenance is much more fun in shady parts of your yard. And your plants will be much happier, greener, and much less thirsty. Watering less means that you’ll need to fertilize less.
Don’t have much shade? These days MAKING shade is pretty easy and inexpensive. All the box stores and lots more places are selling inexpensive aluminum pipe structures meant for instant shade, with heavy plastic covers or canvas. IF you don’t want complete shade, you can purchase 50% or greater shade cloth online and put it onto your pipe structure. For less than $200 you can have 100 square feet of perfect shade for your plants . . half that amount if you want to use the complete shade fabric that comes with the structure, which I recommend you try for this month.
Lowes sells a garden shade fabric which appears to be 75 or 80% shade, in pleasant colors. This is more sun block than you need for winter, but it will serve nicely in August, and it is readily available to all of us locally.
Assuming you have shade now, move in as many pots as possible WITHOUT crowding them. Your goal should always be having no plant’s foliage touch another plant. What? That’s correct, friends. Spacing like that means no scale and no mites and few damaging insects, without using poisons. Just do what you can to eliminate crowding. That makes for easy disease prevention in exotic hibiscus. Trim off horizontal branches to make this goal more nearly reachable. And while moving the pots, remove all discolored leaves left over from sunburn, mites, fungus, or whatever damage. If your plants go into shade clean, they will tend to stay clean without spraying.
If possible, hose down your plants every afternoon, and if you have a Water Wand or can make your own tool to spray plants from underneath with water, you will guarantee that no mites survive this cooling shower.
If you have extra pots, give each potted hibiscus a sleeve, an outer pot to insulate roots. This saves on water and reduces heat stress; you’ll have more summer blooms in Houston if you do.
Treat your shaded plants to a bath of fish emulsion every ten days, or buy and use Organocide to get even better nutrition and insect repulsion. Spray it on with any kind of sprayer, or use a Siphonex to deliver it from a bucket of concentrate. Add some Space City Hibiscus Food and some Epsom salt to make your plants even happier. Get some of this mixture in the pots, of course. These nutrients enter through foliage and roots both.
Summer thunderstorms blowing over your plants? As detailed here earlier this year, consider using 24” or 36” lengths of iron rebar, pushed down through the pot into the ground. I suppose you get a little desirable iron leached into the soil in the pot, also. But the last thing I want to do on a steamy afternoon is pick up pots blown over by afternoon thunderstorms.
And don’t be deceived by those occasional thunderstorms. Buy a wide mouthed rain gauge and install it such that no trees or roof elements overhang it. Only very occasionally do the storms deliver the inch or so of water needed per pot per day to saturate the root ball. It is tempting to use the storm as an excuse not to water, but your hibiscus love nothing more than constancy of conditions, especially moisture in the root zone.
If your community is limiting water use, consider installing a drip system for your pots. You can set it to operate in the very early morning hours, and drip is the most economical use of water one can provide. Double potting and mulching pots will reduce water needs, also. Lowes and other box stores offer easy-to-install systems that do a good job. Online sources offer more choices and better economy.
We find the Roberts Spot Spitters to be most satisfactory with hibiscus, and very inexpensive and easy to install.
Earthworms are good friends in garden soil; in hibiscus pots they are enemies after a short time. They consume the organic matter and convert it to black humus, sticky and poorly drained, causing roots to rot. We have lost many young hibiscus to earthworm invasion, to the point that we recycle hibiscus soil into lawn or garden areas, never into another pot for hibiscus. A weak bleach solution will eliminate them from your pots of hibiscus, as will most any granular insecticide in very small dose applied to the soil in the pot. Soapy water will work, too, but be alert to its probable raising of pH, especially if your irrigation water is alkaline. Most of our fertilizers are acid forming, so this may never be an issue for most of us.
Don’t overlook fans. Inexpensive box store fans do a nice job of keeping air moving in greenhouses where very hot air collects up in the gable areas. Moving air is very desirable for disease and insect and mite control also. And larger fans are wonderful for August work outdoors, directed towards You as you weed or fertilize or otherwise work on your hibiscus. A beach umbrella moved along to keep you shaded can also save your skin and your thermostat from overloading in Houston summers. We also have a misting device on a contorted hard pipe stand, purchased at a big box store. Directed at a worker, this device lowers air temperature significantly, as theme parks have discovered for customers waiting in lines for rides. Over time these do saturate clothing, but it seems a small price to pay for the increased comfort the superfine mist provides. I have even seen mist systems installed alongside gutters, to cool patios and porches in Houston’s hot summers. Perhaps this is a good idea for hibiscus, too.
This time of year it makes good sense to protect yourself from the intensity of the sun. Apply sunscreen as often as needed, wear long sleeves and a hat with a brim, and keep guzzling that water to avoid the pitfalls of dehydration. Sports drinks can replace the potassium lost to perspiration, but bananas are the cheaper and healthier choice.
Keep your cool this month, and try and keep your hibiscus cooler, too.