Question
Hi,
I have eight beautiful hibiscus trees finally planted in concrete containers. I wish to encourage as many blooms for the season as possible.  What would you recommend?
Thanks,
Loretta
Syosset

Answer
Hibiscus Plants are so beautiful, and so easy to grow, I don't know why everyone does not have several at home.

But these tropical plants do need a few specific things to do well.  At the top of the list:  Location, Location, Location.  There is no such thing as 'too much of a good thing' when it comes to the sunniest spot you can give them.  Every photon counts.  No matter how perfect everything else is, if the containers you use are in the wrong location, there will simply be fewer flowers.

People tend to forget this.  Fact is, plants make their own food, and it comes from air, water and light.  No 'plant food' on the planet is going to be able to compensate for too much shade.  Until they figure out a way to put light in a bottle, we are going to have to get our sunlight the old fashioned way.

Hibiscus Plants are so beautiful, and so easy to grow, I don't know why everyone does not grow several at home.

During winter, these tropical plants can prove finicky.  No surprises there. These are tropical plants - used to consistent 12 and 13 hr day lengths.  Get down to 9 or 10 daylight hours a day and they know something's up.  Yellow, dropping leaves is their way of saying I'm mad as hell and I'm not going to take it anymore.

But it is now May, days are longer, the heat is on. Cater to your Hibiscus collection and it will respond with showers of dazzling, brilliantly color petals and sepals all summer long.

At the top of the list:  Location, Location, Location.  There is no such thing as 'too much of a good thing' when it comes to sun and a Hibiscus.  Every photon counts.  No matter how perfect everything else is, if the containers you use are in the wrong location, there will be fewer flowers.

People tend to forget this.  In the back of our heads, we know that plants make their own food, and it comes from air, water and light.  Then the go out and buy 'Plant Food'. No fertilizer on the planet is going to be able to compensate for too much shade.  Until someone figures a way to put light in a bottle, we are going to have to get our sunlight the old fashioned way.

Next necessity: Water.  Tropical Hibiscii needs lots of it. The Town of Oyster Bay is in charge of your water quality; five wells drill into the Glacial and Magothy aquifers that pulse under Long Island. Until 2 or 3 years ago, Oyster Bay's water was so good, it was exempt from health department rules for chlorination.  Homeland Security concerns ended that 90 year old grace period, and the water now has chlorine in it.  The Hibiscus, however, is not sensitive to chlorine.  I mention this because water is sometimes an issue for some plant problems.  It will not be an issue here.

More important that you water thoroughly, drenching the pots.  This is especially critical on hot July days when heat can accelerate evaporation.  Hibiscus DO NOT like a state of thirst.  Hibiscus are thirsty drinkers and aggressive feeders.  If yours are in full sun, and they fail to flower, odds are the problem is just as likely to be a water shortage as a fertilizer shortage.

Room temperature water spiked with a little fertilizer every time you water is the best way to ensure there are enough nutrients to support a Hibiscus Mardis Gras.  Let them dry out between waterings, which sends Oxygen the roots.  Then flood the pots again. Consider a thin layer of mulch at the soil level to minimize moisture loss.

Miracle Gro "Bloom Buster" is a 10-52-10 high-ammonium phosphate fertilizer that would promote flowering on any under-nourished plant -- which Hibiscii in containers will eventually become.  This is a great fertilizer to generate buds and large flowers during high Hibiscus season.  I would not use it more than once a month unless the plants show signs of deficiency.  In between, a balanced liquid fertilizer, thoroughly diluted, will keep them healthy and beautiful.

As temperatures rise, be on the lookout for Spidermites.  The absolute best way to eradicate these ubiquitous heat-loving vegetarians is by sprinkling carniverous Ladybugs around the base of your Hibiscii.  They will hunt down every egg and nymph, licking them right off the leaves; then they'll head off to another infestation (or, alas, to become another Black Flag victim).  You can spray all you want, but nothing beats a hungry Ladybug.  These are available on the internet or at garden centers, including Hicks Nursery on Jericho Turnpike.

Thanks for writing, neighbor.  Send pictures.

THE LONG ISLAND GARDENER