Bougainvillea Leaves: Problems Yours May Have

During my 1st winter caring for them, all of a sudden leaves started dropping. So, I had to ask the question: why are my bougainvillea leaves turning yellow and falling off?

Let’s be honest here, bougainvillea is not a plant I grew up with in the Connecticut countryside. I thought it was some kind of exotic plant until I moved to Santa Barbara 16 years ago where it’s found growing in some form or color on every block. 

Bougainvillea is ubiquitous in warm climates I tell you. Yet in my opinion, it’s a beautiful “weed”. I had no experience growing bougainvillea until a bought a house 16 years ago with 3 of them on the property. 

Turns out, this is one of the most common questions asked about bougainvillea. I’m sharing what I’ve learned (so far!) about this plant that can be used in many ways and gets covered with masses of beautiful flowers.

Note: This post was originally published on 3/16/2016. It was updated on 10/20/2022 to give more information.

Problems With Bougainvillea Leaves

2 photo collage of bougainvillea leaves text reads Bougainvillea leaves: problems yours may have

I’ve grown bougainvillea in 2 different climate zones. I lived in Santa Barbara, CA for 10 years and have currently lived in Tucson for 6 years. By the way, everything I’m sharing here can happen to bougainvilleas growing as container plants too.

Bougainvillea Hardiness Zone: 9b-11

Santa Barbara USDA Zone: 10a, 10b

Tucson USDA Zone: 9a, 9b

bougainvillea dropping yellow leaves
Here are a couple of leaves starting to turn yellow in early fall.  Even though the leaves are dropping, there are lots of flowers already open & lots soon to open.

What Causes Bougainvillea Leaves To Turn Yellow

One of the common issues you may have with your bougainvillea is the leaves turning yellow. I can’t tell you why it’s happening to yours, but I can give you some causes and you can go from there.

Too much water. Whatever your soil type, a bougainvillea plant must have good drainage. Too much water can produce an excess of green growth and less flowering. If not caught, overwatering can lead to root rot. If the soil is too heavy, one symptom is that the leaves will curl.

Too little water. During periods of drought (like here in the Western US) bougainvillea leaves will turn yellow and fall off. If you’re not watering your bougie deep enough, this will happen also.

Pests. An infestation can cause it. You might see the leaves (both yellow and green) curling as well.

Fungal disease. They can be prone to fungal diseases (it’s not common) but I’m not well versed on this subject. Mine has never gotten any.

Nutrient deficiency. I never have fertilized any of my bougainvilleas, even those in pots because they haven’t needed it. Yellow leaves on plants can be a sign of a nitrogen deficiency.

Temperature change. This is the reason some of my bougainvillea leaves would turn yellow and fall off both in SB and Tucson. Some would fall off yellow, and some green. When the evening temps dip below 45-50F, it happens.

This is the B. glabra that grew up & over my garage. When the leaves & colored bracts dropped on this baby, there was a lot of sweeping & raking to do!

What Causes Bougainvillea Leaves To Fall Off

My initial experience with the Bougainvillea leaf color change and drop issue had me scratching my head. What was I not doing? Or, was I doing something I shouldn’t be? 

I did some reading and got some answers but the final confirmation of the cause came when I visited San Marcos Growers that February to pick up some plants for a client in the San Francisco Bay Area. They’re a large wholesale plant grower with an excellent reputation so, with ears open wide, I listened closely to what they had to say.

Here’s the scoop: Bougainvillea plants are tropical plants native to coastal areas. They do great in Santa Barbara where the winter temperatures rarely dip below the low 40s but the tropics it is not. 

One of the causes for those heart-shaped leaves turning yellow (and yes, they turn completely yellow) is environmental. Those cold temperatures in the winter months will do it. 

Once leaves turn yellow, then they’ll fall off. As I said above, green leaves will drop also. Some will hang on and then fall off in late winter/early spring when the new growth appears.

In both Santa Barbara and Tucson bougainvillea is semi-deciduous. Not all the leaves fall off but maybe 1/2 of them. Tucson has colder evening temps and I had one of my bougies hit fairly hard but the leaves hit by the freeze turned dark brown and hung on. You can see more on this below.

Water stress in general can cause this. Another reason why yellow leaves fall off of Bougainvilleas in winter is due to a prolonged dry spell. The last few winters haven’t been too cold but they have been dry. The lack of rainfall in the last 5 or 6 winters has brought on drought conditions so the bougies just aren’t getting the water they were used to.

Conversely, leaves can fall off bougainvilleas in the case of too much water. Established bougies prefer infrequent but deep waterings.

Transplant shock. If they’re happy, bougainvilleas are tough cookies and grow like crazy. Despite this fact, their root systems are very sensitive. I’ve never attempted to transplant a bougainvillea and it can be tricky business if you try it. When I plant bougainvillea, I always plant them in their grow pots. This is another tip I learned from another grower back way back when.

Bougainvillea Leaves With Holes

My experiences with holes in bougainvillea leaves have been related to insects. Rather than go into this subject at length here, you can read more about it below.

Find out what’s causing Holes in Your Bougainvillea Leaves.

bougainvillea dropping yellow leaves
You can see fresh new growth emerging where the leaves have fallen off.

Do All Bougainvilleas Drop Leaves?

It’s interesting because I’ve noticed that some Bougainvilleas drop more leaves than others. And, there are many different types of bougainvilleas not to mention bougainvillea varieties!

I’ve been told that some varieties tend to shed more than others do although I haven’t delved too far into that topic. However, I’ve observed that Bougainvilleas in cooler, shadier, windier, etc parts of town shed more leaves than those in more sheltered areas with direct sunlight. 

There’s a huge hill behind my house that looks out over the ocean, blowing those cool winds. When I was taking a late winter walk up there, I noticed that a 2 block long hedge of bougainvilleas (I believe they were B. San Diego Red) had almost completely defoliated. But, once the weather warmed, they all started to leaf out like crazy.

bougainvillea dropping yellow leaves

Best Time To Prune Bougainvillea

I’ve done many posts on bougainvillea pruning so I not going too in-depth on the subject here. I’m including this short blurb on pruning because I’ve found that a great time to do it is when a lot of the leaves have fallen off and before all the new leaves have opened up. You can better see the structure of the plant prior without the dense foliage.

I always wait until the colder months have passed and the nighttime temperatures have warmed to over 45F to prune. In Santa Babara, it was mid to late winter, and in Tucson late winter to early spring.

The pruning that I do at this time is the one that sets the framework shape and size-wise as to how the bougainvilleas will grow for the rest of the season. I find it easiest to do this before the leaves come out and all the foliage is in the way. And remember bougainvillea, blooms on new wood so pruning will encourage flowering.

My B. glabra, which you’ll see a couple of photos up and in the video below, was a flowering machine. It puts out a big show of magenta/purplish color off and on during the growing season which is 9 months out of the year. It grew up and over my garage which sits at the end of a long, narrow driveway. It got a major “WOW” from anyone who saw it. That plant was an adventure in pruning!

By the way, this is How I Prune and Trim my Bougainvillea to Get Maximum Bloom. For more on pruning, check out Bougainvillea Pruning 101.

See how my bougainvillea glabra looks in winter:

What To Do

It depends on what’s causing them to fall off. I’ve touched on that above.

The cause with my bougainvilleas both in Santa Barbara and Tucson was environmental. It happens in late fall/winter. The reason is the colder evening temps. and prolonged dry spells.

So, for this reason, there are two things you can do about those leaves falling off bougainvilleas: #1 is to just let them be and fall where they may, and #2 is to rake or sweep them up. 

It’s part of the plant’s natural cycle, and because we don’t get any colorful foliage displays in these parts, we’ll take it as our version of fall!

bougainvillea dropping yellow leaves
Bougainvilleas shed all those colorful leaves (technically called bracts) after every bloom cycle.

FAQs About Bougainvillea Leaves

Do bougainvillea lose leaves in winter?

In my experience growing them in two different climate zones, yes. They lose a good portion of their leaves. In Tropical climates, I’ve heard they stay more evergreen.

Why are my bougainvillea leaves curling?

Common causes that I know of are: not enough water, not getting enough light, or some type of pest.

Are bougainvillea leaves poisonous?

I can’t give you a definitive answer on this one. I refer to the ASPCA website for this info, and they don’t list bougainvillea. People can have bad reactions to the thorns skin-wise, but in terms of the leaves and papery bracts of the flowers, it’s best to deter your pets (and young children) from eating them.

Why are my bougainvillea leaves dropping?

There are a few reasons. It could be too much or too little water, transplant shock, pest infestation, not enough light, or a temperature drop.

In my experience, it’s their natural cycle of shedding in late fall/winter so they can put out fresh new growth.

When does bougainvillea lose its flowers?

The colored parts of the bougainvillea aren’t flowers. They are leaves. The technical term is bract. The flowers are the tiny white centers.

They lose their flowers after every bloom cycle, which is 2-3 times a year. They also lose them in colder temps, when the light levels are too low, or if they’re too much or not enough water.

After the leaves drop and the new growth is well on its way, then those bougainvillea blooms appear. These gorgeous plants are somewhat of a mess, but well worth it in my opinion!

Happy gardening,

Signed by Nell Foster

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  1. Hi Karen, I live in Miami. About a month ago I bought 3 bougainvillias, they are in 17 inch pots. When I planted them, I didn’t put rocks in the bottom of the pot, just soil and the plants directly into the pot (which does have a drainage hole). I water them once a week. Recently, the leaves started turning yellow and falling. One of the plants is worst, and barely has any flowers/leaves left. What am I doing wrong? Please help!

  2. I got a potted plant as a gift in the summer in South Louisiana. It was not in bloom at all. Where I first placed it I realized it would never get any direct sun. So, after a few days I moved it to another location where it would get a several hours of direct sun and gave it a shot of epsom salt. It got drenched three days in a row from heavy rains.
    I was worried that it had too much water as I started to see the bottom leaves start to turn yellow and then fall off. Now half of the leaves have fallen after turning yellow. I don’t see spider mites. What is killing my plant? Combination of everything I did from epsom salt, shock of getting too much sun and too much water all within a week period of time perhaps? What can I do to try and save it?

  3. Hi Diane – Even bougainvillea is a tough plant, they don’t like to have their roots disturbed. The moving in tandem with everything else could be doing it. Nell

  4. Hello Nell,

    I hope you can help me and my bougainvillea.

    I`ve had this for quite a few years, in a pot on a fully sunny balconi.
    For some years it was not really flowering for me, and then in Autumn time (I live in Japan), it started to bloom a lot, gorgeous. The leaves though were never thick deep green; they were always thin (even though big) and paler in color.

    It was growing so much that the size of the pot became very disproportionate to the length of the branches during the growth period.
    Even though I know bougainvillea do not like to be touched, I needed to give it a repotting.

    Next spring, I noticed that at the bottom of the pot hole there was a cushion of something…roots! (The rooting system seemed to have like the more space and roots came out from the hole of the pot).
    Unfortunately I had to repot again…

    By Autumn time, when usually it is the time this particular one flowers, here it went again…! Another cushion of roots; I could not believe it.

    Well, you can understand that was 3 shocks in a year, and both last year and this year no signs of blossoming. New leaves grow, still thin and pale (even though they get big) and with a kind of pest situation going with the leaves at times.

    I prune it in the hope that next time around the leaves will grow healthy and it will rejuvenate (and for the pest situation I try to control it using Neem oil).

    What can I do?

    First it seems to me the leaves being week and pale are lacking something.
    I give it an organic slow acting balanced solid fertilizer in the spring and in Autumn, and I boost that with the same organic liquid fertilizer.

    I hope you can help my bougainvillea. I miss its beautiful blossoms (even though its leaves were never thick and dark green, but thin and paler).

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