While the flowers on these pages may be very enticing, you maylook out your window, see snow and ice, and wish you were living insouth Florida, Hawaii, Singapore or some other tropical area where youcould grow tropical hibiscus.
Tropical hibiscus need a lot of light to bloom andperform well. Full sun from dawn to dusk may be too much during summer,but during short winter days, they need all the light they can get.Even with a lot of light and ideal temperature and humidity during thewinter, they will likely bloom and grow less.
Before we get into it, manypeople want to know, "How do I tell if I Have a Hardy Hibiscus or aTropical Hibiscus?" and "Will My Hibiscus Overwinter Outside?"You need to know which one youhave. Unfortunately, garden centers, nurseries and home improvementcenters lump all hibiscus together.
If your hibiscus has glossy deep green leaves, 3-6" flowers of red, pink, orange, yellow, double orsingle flowers, it is probably a TROPICAL hibiscus. While many commongarden varieties have the 3-6" blooms, many of the hybrid varieties oftropical hibiscus can have blooms around 10" in diameter under idealconditions.
Another way to check is if theflowers are salmon, peach, orange, or yellow, or double flowered, thenyou probably have a TROPICAL hibiscus. Hardy hibiscus do not come inthese colors or in doubles! Many tropical hibiscus flowers have morethan one color in a bloom either in bands or as spots.
If your hibiscus has dull medium green heart shaped leaves, dinner plate sized white, pink or redflowers with HUGE, bomb shaped buds (2-4" in length!), it is aperennial, hardy hibiscus.
Hardy hibiscus need verylittle care over the winter, they are root hardy to about zone 5 withno protection. They die to the ground each year.
If you have a tropicalhibiscus, remember it is a TROPICAL. They will not tolerate more than anight or two of light freezes. Even one hard freeze (below 25) couldkill the plant. These plants are native to sunny, warm and usuallyhumid tropical places.
They detest cold, rainyweather and cold, wet soil. They will not reliably survive outdoorsnorth of zone 9. In all other areas, it may be a good idea to bringthem indoors BEFORE temps regularly drop below 40-45 F at night toavoid any damage.
Treating your tropicalhibiscus correctly will give you years of enjoyment. But remember, theyare not immortal! Some are spent after 4 or 5 years in a pot and shouldbe tossed away at this point. Try some of the many and never ending newhybrids being developed!
Getting Tropical HibiscusReady to Come Inside in the Fall/Overwintering Indoors
If you want to keep yourhibiscus and grow them again the next season, you will needtobring them indoors before the night temps drop much below40° F. They will need a bright or sunny area, or underfluorescent lights. The optimum temperatures indoors seem to be between55 and 70. The cooler end of that temperature range will producefar fewer insect problems later in the winter. If they are kept in agreenhouse, keep them cool (55-65) and water when they are dry.
Ideally if you want to bringyour hibiscus indoors to over winter them, they should be grown in potsoutside all season, not planted directly in the ground. The problemwith planting in the ground is that when you dig them up in the fall,they are weakened by yanking them out of the ground and many times theywill rot before they produce new roots in a pot. They should be kept inrelatively small pots for years (10-14" in diameter is fine). You caneven sink the potted plants in the ground in summer and then just pullthem up , pot and all in the fall, wash off the pot and bring itinside easily with no shock to the plant in fall.
- Before you bring theminside,cut back your plant(s) quite a bit, to within 4-5" of themain stems. This does a few things: it will help eliminate the bugs andinsects that hide in the plants BEFORE they get inside. They like tohang out in the tips of the branches, in the newest growth. Also removeany dead leaves, stems., old flowers or debris in the pots, or on theplants.
- If you want the bestchance of having healthy, vigorous plants with flowers next summer,your plants need to rest indoorsduring the shorter daysfrom October till Feb. or March.DONOT push them to keepblooming indoors and leave them full of old foliage.
- After cutting back yourplants,but before they come inside, be sure and hose themdown, making sure to blast the stems, under the leaves, etc. Letthem dry thoroughly and bring them inside. This will eliminate the needfor any insecticide at all. if you must spray, insecticidal soaps andneem oil work well. Drench the upper and lower parts of the leaves, aswell as the stems and let dry thoroughly outside for a day or so beforethey come inside.
- Theleaves willprobably turn yellow and fall off when the plants are broughtinside, this is normal. They will regrow when they are ready. Inthe meantime, water very sparingly! Do not keep the soil wet. It isbest to let the soil become almost bone dry before soaking it again. Donot let any water sit under the plants in saucers, etc.
- Your plants will restandmay not produce new leaves until late February or March. Thisis normal too.
- Realize thatmanytimes, hibiscus never bloom well again after the 1st winterinside.There is not much you can do about this. It appears thatthe generic grocery store, Costco, Home Depot, etc., hibiscus tend tonot bloom well again after the 1st season. The new large floweredhybrids seem to perform much better year after year. This is anobservation based on my experiences over wintering hibiscus. Yourhibiscus experience may vary.
- Theother option is tobuy some new hibiscus each year, enjoy their prolific flowers for thesummer and toss them in the fall. That way, you are guaranteed lots offlowers each summer.
There are people who grow these plants year 'round in the northern U.S. and Canada, Sweden and NOT using green houses! Unless you take some extra steps, such as using artificial lighting, you can't expect the same lush growth and bloom quantity when your plants are spending their winters inside and under less than tropical conditions. But, they will be ready to reward you for your efforts once they are outside again and the warm weather arrives. (However, if you do have a greenhouse...)
If you aren't too far north, building this will help and is easy to do.
There are reports of another way of over-wintering these tropical plants.
Tropical Hibiscus and TheirEnvironment: Gimme Shelter
Insect and Disease Problems: Don't BugMe, I'm Already Sick
Watering and Moisture Tips: Water YouDoing to Your Plant?
Potting and Containers: The Heart and Soilof the Plant
Repotting and Fertilization: Feeding theMasses Getting Ready for Summer: Living inParadise Winter Care:A Shower a Day (or atleast occasionally), Keeps the Aphids at Bay!Tropical Hibiscus and TheirEnvironment: Gimme Shelter
Since several hours of temperatures below freezing can bedeadly to hibiscus, before the mercury drops, growers move their pottedplants to an inside location where they will get, perhaps, 3 or 4 hoursof direct sunlight a day. (Supplementing with artificial light (please visit) may also be an option.) Here theywill stay for a few months. Some leaves may turn yellow and drop andsome buds may fall during the adjustment period. If chemical sprays areused to control insects, these need to be used before the move.
Feel free to prune your hibiscus to fit the space where itbe indoors. It is not important WHERE you make the cuts, as long asthey are made cleanly with a sharp pruner. Just remember that you willnot see much (if ANY) new growth from this pruning.The hibiscus growthslows down considerably during the late summer/fall and winter.
This is also a good reason NOT to repot in the fall. Thehibiscus will not generate new roots easily at this time of year andwill probably suffer from root rot before it gets re-established.
Insect and Disease Problems: Don'tBug Me, I'm Already Sick
Once inside, if nothing else is available, soaps such as castile and Murphy Oil Soap orunscented liquid dishwashing detergents such as Dawn can be used in a onetbspn per gallon of water solution. These can cause leaf damage which can lead to unhealthy plants -- see this University of Florida advice. Horticultural soaps are recommended. Bigger pots are suggested for longterm use as an inside plant. Nothingsmaller than a 10" pot. Using 14" pots, hibiscus have been known tothrive for almost 10 years.
Watering and Moisture Tips: WaterYou Doing to Your Plant?
Don't over-water, keep on the dry side, but remember thatindoor air may have a drying effect because of low humidity. Mistingthe leaves at least daily is desirable in most instances. It may alsobe helpful to place each pot on a large tray containing gravel. Fillthe tray with water up to the top of the gravel. As the waterevaporates from the tray, humidity will be higher around the plants,especially if they are not in drafty areas. Humidifiers are alsobeneficial.
To gauge how wet the soil is, try lifting or dragging the pot. Soggy soil is heavy, while nearly dry soil is surpringly light.
Tropical hibiscus do NOT thrive in soil that stays too wet. A small plant with few leaves needs much less water that abig leafy plant. Do NOT over-water!Potting and Containers: The Heartand Soil of the Plant
The soil in pots is very important. The usual "pottingsoils" are not recommended. They can be much too heavy and can hardenwith a few waterings. One recommendation is to use a light soilless mixsuch as PRO-MIX or Sunshine Mix which is available at mostnurseries/garden centers. These are soilless mixtures consisting ofperlite, vermiculite, peat moss, with some bark. Jungle Mix, aprofessional seed starting mix, available from some home/gardencenters, also produces good results. Remember that tropical hibiscus dobest with very good drainage.
Repotting and Fertilization:Feeding the Masses
In late winter, scrape off the top 2 inches of old pottingsoil and replace it with fresh soil. You do not have to be gentle; youwill be scraping old roots, too. Go for it! Then add Osmocote slowrelease fertilizer "for indoor plants" per the label instructions. Atthis same time, prune as severely as you like, using sharp, cleanpruners and just above a node. Occasional use of a 20-20-20 watersoluble fertilizer is also appropriate. The plants will respondbeautifully to this treatment.
Getting Ready for Summer: Living inParadise
Once the night temperatures are consistently above about55° F (13° C) or so, you can think about putting your hibiscusoutside again.
Here's a quick list of things to remember:
• gradually exposeyour hibiscus plant to the outdoors.Place your plant in a shady or protected spot for a few days and thengradually increase the amount of direct sun it receives each day forabout 10 days or so. After that, you can move it to it's final sunnysummer spot. If you don't do this, your hibiscus leaves will fry andsunburn, just as you would if you were out in the hot sun for 8 hourswithout sunscreen after being indoors all winter.
• prune your plant now if you wish to change the shape orheight or induce a bushy flowering plant.
• this is also the time to refresh the soil or repot yourplant if needed (rarely- they love to be potbound!)
• once outside, spray down both lower and upper leafsurfaces with the garden hose to remove any indoor dust or bugs. You'll be amazed how it rejuvenates your plant.
• after your plant has been back outdoors for 2 or 3 weeks,you can start to fertilize again with your favorite fertilzer.
• avoid saucers with standing water under your hibiscusplants- they can cause root rot and leaf drop.
It's perfectly normal for your plant to have yellow leavesor even drop some leaves in response to the stress of going backoutside. Different varieties of hibiscus may have their own"personalities" and may not perform uniformly when conditions change.
If you follow these general guidelines, your plants will behappy and thrive for many summers.
Winter Care:A Shower a Day,Keeps the Aphids at Bay!
During the winter indoors, most hibiscus may develop aproblem with aphids or white fly. One of the non-chemical ways to helpwith this is to give your hibiscus a shower!
Cover the top of the pot snuglywith aluminum foil orheavy plastic (to keep the soil from washing out and making a mess,also to prevent waterlogging the roots) and make sure that youcompletely seal offthe pot around the stem. Then just stick theplant pot and all in the shower, turn on a low to moderate spraydirectly on the leaves. Use lukewarm to comfortably warm (NOT HOT!!)water.
If you have a movable shower head or attachment somuchthe better. Be sure and try to get the undersides of theleaves if you can. You can even turn the pot on its side if you sealthe top of the pot with the aluminum foil good and tight (use rubberbands). Do this for about 5-10 minutes.
This may sound extreme, but it sure gives your tired, dusty,buggy plant new life. Even if you do this only once or twice during thewinter, you will notice a difference.
It will not eliminate the pests but will certainly controlthem and your hibiscus will thank you.
If you have questions on these recommendations, you can directthem to the source, Boca Joe, for most of theabove information.
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