Question
QUESTION: I bought a persian shield this summer and it is beautiful.  Then I realized it will not withstand the winter in zone 6 (KY).  Can I dig it up and keep it for next year? Can or will it go dormant or should I keep it in partial light?

ANSWER: Be the first on your block to grow the tender, tropical, exotic Persian Shield ('Strobilanthes dyerianus' to botanists) -- but do it indoors as temps drop south of 50 degrees.

It would be a hopeless dream to try to keep this beautiful shrub through winter at your old Kentucky home. Don't think it will be easy to get it through the cold season indoors, though.  This shrub needs the steamy atmosphere that recall its beginnings in the Burma jungle.  Heat plus H2O.  Makes growing tropical Orchids look simple.

It is probably better odds that this shrub be directed to go dormant, then protected until temps turn around in early Summer -- yes, early SUMMER.  We're not talking Spring flings here.  This is a Zones 9-10 native.  It doesn't just hate ice.   It hates all things chilly.  If you need a sweater, so does your Persian Shield.

Keeping any non-hardy plant dormant but not too cold, not too hot, for more than half the year is very tricky.  The time you spend on this balancing act is enormous.  That, to me, makes this Plan C.

Back to Plan B (Plan A being the fantasy of protecting it outside in Zone 6, hoping the roots won't notice how cold it really is up there.  This poor plant is simply not built for brisk weather.)

Bring your shrub in -- at this point, do that TODAY! -- and figure out where it can get lots of light without drafts or air that's too dry.  Then get yourself a good humidifier, and point it at this plant.  That's not so bad, really.  That humid air is good to breathe, too.

While you're at it, why not get yourself a couple of Orchids?  Hausermann's in Chicago will send you some gorgeous Winter bloomers right now.  They'll grow happily next to the Persian Shield.  No surprises there.  They probably do that in Burma, too.

Thanks for writing.  Please remember to rate me when you're done.  Any followups?

THE LONG ISLAND GARDEN

---------- FOLLOW-UP ----------

QUESTION:   Let's talk more about "Plan C".  When I dug the plant up there were 2 stocks, so I divided them and put them in 2 seprete containers.  One plant I will follow "Plan B" and the other I would like to try making it go dormant (cause that would really be ideal).  So please, more advice.  
 Thank you for the wonderful answer from my first question.

Answer
Yes, it is true - there is no such thing as a true gardener who believes there is such as a thing as "It can't be done."

So let's go there.  Plan C.

This remember is difficult.  OK, not impossible - is anything really impossible? - but very, very hard.  I am not telling you this to discourage you.  I am telling you that when the tough gets going, don't ever let it cross your mind that someone else would be able to do this without any trouble.  If you were a botanists with a PhD and a Noble Prize in Chemistry, you would have a LOT of trouble getting this to work.  Just to let you know.

When tackling this project (Plan C), we have to ask a question: What triggers dormancy in Strobilanthes dyerianus.  And by the way, if you're going this far, you may as well learn that name by heart.  This way, if you get caught in an elevator with a famous botanist or gardener, or maybe Ralph Snodsmith or Jerry Baker, maybe Martha Stewart, you can discuss this plant like adults.  Some experts refer to it as Perilepta dyeriana.  Don't let that throw you.  Same plant.  Exactly the same plant.

Herewith, a color photo suitable for framing, courtesy of University of Georgia green thumb Paul Thomas:

www.insectimages.org/browse/autimages.cfm?aut=37590

Very nice photo, Paul.

I confess, I have not had the pleasure of turning my life inside out to grow Strobilanthes here on tropical Long Island.  So we have to find experts who do know.

The leaves are the most striking feature of Persian Shield.  Their irridescence and coloring will most certainly change as the air cools -- gradually, over a period of weeks, if you do this right.  

Luckily, some parts of the world are trying to grow LESS Persian Shield.  In warm climates friendly to this species, it has become one of the most menacing weeds in those regions.  Research is being conducted on ways to control it.  Other thinktanks want to understand how to make it grow better, because this is a very popular (and common) cash crop on the West Coast in places like San Francisco.  To do that, these researchers have to know what makes it tick.

This Masters candidate for example wrote her 114-page thesis on 'Flowering Control and Production of Strobilanthes dyerianus.'  Lucky you:

scholar.lib.vt.edu/theses/available/etd-04222003-150254/unrestricted/EGThesis.pdf

First paragraph of this thesis and I quote: 'A problem in production is that over-wintered stock plants often flower.'  That is a problem for growers, not for you.  Nurseries use cuttings to multiply their stock; anything that interferes with a successful mass propagation program interferes with profits.  This brings up yet another option for you -- Plan D, Cuttings.  Provide generous amounts of bottom heat and upper humidity to boost your odds at this time of year, but if Plans B and C should prove disappointing, you will have those Plan D cuttings to work with come next Summer.

Back to the lab.

Researcher Erin Elizabeth Gamrod comes to believe that 'Bud initiation seems to be associated with the onset of Winter' based on interviews with growers.

But Gamrod's study is inconclusive.  As you page through this study, note that routine temps can run as high as 75 degrees F (24 degrees C) to as low as 57 degrees F (14 degrees C), indicating this range will produce thriving Persian Shields.  The plant grows by leaps and bounds with the warmer days, and very badly under the cooler conditions.

Gamrod grew her plants in Fafard 3B Soilless potting mix.  The recipe is recited on under 'Materials and Methods' for the new plugs received from California-based wholesaler EuroAmerican Propagators: Peatmoss, pinebark, Perlite and Vermiculite.

But don't try this mix at home.  Soilless mixes are selected here for their research usefulness.  Not because they're good for plants.  Regular potting soil is almost certainly going to be superior for your purposes.

So, how do we make this plant go dormant?

There is no literature (therefore no research) on this subject.  We do know for a fact though that moisture and warmth are necessary for active, optimal growth.

So I would leave the lucky plant outside and let it acclimate, gently, to lower and lower temperatures.  If you find the weather report predicts a sudden, much colder snap, lower than 10 degrees from the night before, place it somewhere protected -- NOT hot, just protected, like the garage or even the family car.

At the same time, use a light hand when it comes to watering.  This is probably the trickiest part of the exercise here.  These cooler temps propel the health and populations of disease causing bacteria and fungi, and moisture is ideal.  You want to promote dormancy, not disease.  Lower the watering rate until you are spraying the leaves and no longer watering.  If the soil gets dry, bottom-water to keep it just the slightest bit damp.  (Remember, roots get bacterial and fungal diseases, too.)

I would recommend against any kind of prophylactic fungicide or bacteriacide.  They do away with the good microbes that keep bad microbes in check.

Watch your plant grow less and less, until it is dropping leaves and appears to be dieing.  Then place somewhere it won't freeze but won't be warm enough to grow, and wait for Spring.

When growth resumes, bring out the champagne and call me.

THE LONG ISLAND GARDENER