Question
QUESTION: I just bought 2 bougenvillea from a nursery and only few days later, I found that all the leaves are drooping. It was all lively and healthy when I got it.  There are still flowers on them. I can lift the plant right out of the pot. It is full of roots. Is the drooping due to lack of sunlight, lack of soil or water?  Please help ASAP. Thanks.

ANSWER: Leaf drop on Bougainvilleas can have several causes, and the answer here depends on where you are writing from.

If you are Northward, you should know that Leafdrop is part of the Bougainvillea's normal cycle.  They do this naturally toward the end of the Summer or early Fall.  It's nearly Fall, and leafdrop is right on schedule.

If you are Southward or someplace tropical, you should know that these plants are normally heavy drinkers while in active growth.  When a new specimen is too dry, too long, you get leafdrop.

If neither of the above applies, you might have a problem.  Leaves dropping like flies may indicate disease caused by watering way too much, way too often.

The Plantfacts website devotes a page to the Bougainvillea glauca.  You might like to read it:

http://www.plantfacts.com/Family/Nyctaginaceae/Bougainvillea.glabra.shtml

Let me know which answer seems to fit your situation.  Thanks for writing.

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

QUESTION: Thank you for responding. The leaves actually do not drop yet.  They droop like no life is in them. I live in Maryland so it would be Northward. Recently, the temperature has been on the cool side around 60's. Could it be the sudden change in temperature? What can I do now? Thanks

ANSWER: So we have here a case of 'drooping' vs 'dropping' -- my mistake.  When a Bougainvillea, or any plant for that matter, wilts, you know that water is not getting into the roots and around the plant.

I had a Cestrum -- similar to a Bougainvillea -- hardening off outdoors one autumn when I was living in Upstate NY.  Temps were regularly reaching 28 degrees F and it would be getting much colder before Winter set in.  It was growing like a champ in the sub-freezing nights, even though Cestrums are not really hardy plants.  Anyway, I suddenly left town for a few days on business and as I was leaving, I realized it was about to get REALLY cold where the Cestrum was.  So I arranged for a friend to 'rescue' the Cestrum from its cold-front fate and bring it indoors.  Trouble is, this friend carried the poor Cestrum into a house that was probably 77 degrees F or so; as if on cue, the Cestrum wilted instantly, practically collapsing, and quickly died in his arms.

In efforts to resuscitate this collapsing plant, he began watering the desperate, wilted Cestrum.  To no avail.

By morning it was a pile of soft, dark green chlorophyll colored phloem and xylem.  See, the hardened off Cestrum was unprepared for the instant tropical temps he provided.  It could not distribute moisture fast enough through its vascular system.  This Cestrum did not need water.  It needed to get out of the room and back outside, then endure gradual steps to turn up the temps indoors.  The roots were adjusting to the cool temps; water could not flow through them.  The wilting had nothing to do with thirst.

In the case of your Bougainvillea, which is also wilting, I suspect it is reacing to severe transplant shock and root stripping.  These plants have very delicate root hairs.  Any disturbance will wipe them out.  Some growers recommend you cut the plant out of its container to plant it, rather than popping it out, to minimize reaction.  You do what you can do.

But Bougainvilleas do not like to be moved or to be repotted.  Depending on the amount of shock they're dealing with, they wilt, a little or a lot.

Note that it is this same delicate, fickle root system that reacts the same way to overwatering, which kills root tissue (wilting is the first symptom).  A Mold called Phytophthora attacks Bougainvillea roots, so they wilt.

The change in temperature?  Depending on how SUDDEN the change was, it may or may not explain this wilting behavior -- this drooping.  Compounded by the completely new location since you purchased it, a new watering schedule or even too much water, the wilting is probably caused by all of the above.  That's my theory.

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

QUESTION: So I think that it wasn't the overwatering, and I didn't repot it yet, so it must be the temperature shock like your plant. It went from 65 to 80 degrees. Should I take it outside and leave it out now? What is the lowest temperature that it can safely stay outside? But, eventually I would have to take inside once the cold sets in. Then it gets shock again. In case of the Mold, is there anything to treat it? How can I tell if ther Mold is there? Help...what should I do now?

Answer
First off, Cynthia, I am sorry this is something I could not get to sooner.  I know you have been worrying about this plant for several days now.

I should point out that my well intentioned friend was carrying the cold-acclimated Cestrum, which had been hardened off over a period of months in a sheltered location and would have survived an extended exposure to freezing weather at that point, into a dry blast of warm air.  If he had had access to a toasty fireplace I am sure he would have set the Cestrum right there in front of it, figuring any Cestrum would be very pleased with this warm, comfortable space.  He knew nothing about the cellular changes that take place for a plant to survive cold weather, and further changes that make it capable of enduring weather that freezes water or colder.

This is a very different scenario from the one your poor Bougainvillea has endured.  Hardy to Zone 10, these are nevertheless considered fairly easy choices as houseplants go.  Have a look at what About.com's resident Phoenix Gardening expert Judy Hedding has to say about these:

http://phoenix.about.com/od/desertplantsandflowers/a/bougainvillea.htm

To make Hedding's short list of recommended 'Easy Plants for Desert Landscapes', they must be 'hardy, low care, relatively drought resistant, easy to find, pretty cheap to buy, and provide lovely color many times during the year.'

Pay special attention to the key word in the title of this list:  EASY.

It does sound to me like your Bougainvillea was having an especially difficult day with all the things piling up and its limitations as a fairly tropical plant that needs warmth and protection.  Any of those problems individually might not be a problem.  But add them up and suddenly it's like you and me getting out of bed on one of those days you wish you just had not done that.  Too much at once.  Plants, as they say, are like people.

The watering of these plants is tricky, and you are just going to have get the hang of that if you have not already.  It is my understanding that Bougainvilleas will endure gradual freezing temperatures; they just have to surrender their leaves and become dormant until Spring.  Mold and Fungi are moisture problems; eliminate the moisture, step up the air circulation, and the problem solves itself.

The best thing you can do now is to keep Status Quo.  Don't over-tend this plant, don't repot it until it is good and ready, don't over-water.  Any change is a very stressful change at this point and if it continues to be stressed, it will head further and further downhill to the point of no return.

Water it, but DO NOT overwater.  Make sure the soil is not cold.  If the plant is wilting and the soil is moist, DO NOT WATER; a stable temperature and roots that are not left in soggy soil is probably what is needed right now.  Remember it needs Sun when you bring it indoors, but also remember that temperature change is STRESSFUL and must be done carefully and patiently.  That is a hard thing to do.  Good luck.  Any questions, please let me know.