Bougainvillea Help - overwatering, fungus, or something else?

[zezima]

I just picked up my first bougainvillea from a nursery about a month ago. It has been doing alright but has lost most of the bracts since I got it which I expected.

I have added bougain to the top of the soil and have been trying to water it only when the pot feels light or the leaves start to wilt which has been ~10 days on average (as shown in img5).

I have noticed some older leaves started to turn black which concerned me (I removed them) but now I am seeing new growth on the tree which is turning black which is a lot more concerning. I've also noticed the trunk appears to be black in some areas and black spots in some parts of the tree.

My question is, what am I doing wrong? Am I overwatering it? Under watering? Is it some sort of fungus or pest?

Thank you in advance for any help or suggestions!

 

[Carol 83]

Hard to tell for sure but one thing bougies won't tolerate (and they tolerate alot) is overwatering. If you only water it every 10 days the soil is definitely not free draining enough. I would really watch the watering and repot it this summer to a better draining soil.

 

[zezima]

Hard to tell for sure but one thing bougies won't tolerate (and they tolerate alot) is overwatering. If you only water it every 10 days the soil is definitely not free draining enough. I would really watch the watering and repot it this summer to a better draining soil.

Thanks for the tips.

I actually think I found a couple aphids under some of the new leaves so I sprayed everything down with a dishsoap/water mixture.

I can look into repotting but it came from a bonsai nursery and should be in an akadama-based bonsai soil already. In a more free-draining soil would I be watering more frequently than every 10 days in the winter?

I’m used to watering my BRT so I water very thoroughly when I do. Maybe I should water less thoroughly? After watering and spraying everything down today there were more black leaves/bracts.

It appears to get worse immediately after watering.

I could share some more photos if it helps.

 

[lehigh4me]

I have about 40 bougainvillea some in regular soil and some in bonsai soil. I water the ones in bonsai soil on average about every 4 to 5 days and the ones in soil about every 7 to 10 days. Mine are in a cool (62 degrees) basement under lights. for 14 hrs a day.
They usually drop all the leaves around this time of year.
When the leaves are turning black it usually because they get to dry. But I don't water heavily until they start getting good new growth so I don't drown them.
Good luck.

 

[ShadyStump]

I'm no expert on bougainvillea, but it seems the folks who would know are thinking watering issues.

Are you familiar with the chopstick trick?
Jab a wooden/bamboo chopstick or similar into the soil, all the way to the bottom of the pot, and leave it there. Use it as a dipstick to check soil moisture, and only water when the stick is all but dry.

Many smaller nurseries supplement their stock with mass produced stuff that rarely comes with bonsai specific soil, or themselves use more organic soil to cut costs or reduce workload. It's something to look for every single time.
I tend to use more water retentive soil on all my trees, otherwise, in my climate, I'd have to water 3+ times a day in summer. It does make watching the watering in winter a bit more tricky, but life is all about compromise after all.

 

[zezima]

I have about 40 bougainvillea some in regular soil and some in bonsai soil. I water the ones in bonsai soil on average about every 4 to 5 days and the ones in soil about every 7 to 10 days. Mine are in a cool (62 degrees) basement under lights. for 14 hrs a day.
They usually drop all the leaves around this time of year.
When the leaves are turning black it usually because they get to dry. But I don't water heavily until they start getting good new growth so I don't drown them.
Good luck.

Thanks for the info. What was interesting was they mostly turn black when I water them after waiting for 10 days or so. Is that consistent with them not getting enough water? Do you usually water thoroughly when you do water or just enough to get them decently wet again?

It's been about about 3 days since I watered and created this thread. I just checked again with a chopstick and it was slightly moist so I will hold off another couple of days and water again. I'm still trying to figure out what's best since I was initially told to only water when they start to wilt.

 

[lehigh4me]

In my opinion if you wait to water until they start to wilt on a consistent basis some roots will die off, then if you water them fully they cannot absorb all the water. Then the leaves die and turn black. That is why if they get dry enough to wilt and lose leaves, I don't overwater. I wait until they start growing again and water fully when they are growing.
I water by the weight of the pot. If the pot is lighter I will water and if it is heavier I will wait a day or two. After you get used to Bougainvillea you can tell when the leaves are getting low on moisture. They will sag slightly before the actually start wilting. It is best to water when they start to sag than wait until they are actually wilting.
Hope that helps you out.

 

[Bonsai Nut]

Just mirroring what people are saying here. They have touchy roots. We had them all over our landscape in SoCal and once established they could go 6 months without a drop of rain. They do not like wet feet. It is one of those trees that I used to feel thrived on neglect. This photo is of a bush I actually planted about 15 years ago... and did nothing else but trim for shape. Look at that nasty dry clay soil...