Q: I have a bougainvillea plant and It just finished a full bloom. First time in 3 years it gave such a beautiful show. I have it as an indoor plant. Since the bloom all the leaves are falling off. I know I need to prune, but is there something that I'm doing wrong? I followed all instructions, watering, light etc. Please let me know how to correct the problem. Franka – Cambridge, Ontario, Canada.
A: Hi there, Franka from Canada. It is good to know that you are checking us out here in Brisbane from that beautiful country of yours, Canada. I was there on holiday and business for a very short two weeks about two years ago. WHAT can you see in two weeks? Very little! I holidayed with a good friend of mine in Toronto for a week … and caught some salmon in one of your lakes. The second week was in Vancouver … checking out that fantastic garden, Butchart Gardens in Victoria, whilst I was there. Have you been to Butchart Gardens? If not … you HAVE TO go there. You will not regret it.
NOW … back to your question.
Bougainvilleas do BEST in full sun throughout the day. They are very drought tolerant plants when grown in-ground, but respond somewhat differently in a pot. The idea is to keep the pots on the ‘drier’ side, but NOT let the soil dry out altogether. Do not water them too frequently. You may let the top layer of soil in the pot dry out somewhat, provided there is still some moisture lower down … not WET, but moist.
When grown as an indoor plant you need to give them as much DIRECT sunlight as possible … at least a minimum of 4 full hours of direct sunlight. The more the merrier. After that, you need to give them as bright an ‘indirect’ light as possible. In conditions of insufficient light the plants will flower less and will lose their leaves.
Watering of bougainvilleas in an indoor situation is critical. ‘Too much’ water, and ‘insufficient water’ can both lead to leaf fall. They need less watering in winter and more in summer. This regulation is important. A liquid fertiliser with high contents of phosphorous and potassium are best for bougainvilleas, watered in a little at a time every fortnight or so, and during the spring and summer.
Ease off from mid-autumn to no fertiliser at all until the next spring. (Readers, please note - This latter bit refers to the situation in Canada, and NOT for Brisbane. Our bougainvilleas in Brisbane actually put on an excellent show of blooms in autumn and winter).
Maybe you struck it ‘lucky’ by doing just the right thing this year for your plant to bloom at it’s best? Can you think back, try and figure out what you did this year, and then replicate that hereafter?
Yes, you do need to prune your plant when growing it in a pot. Always prune soon after it has flowered and dropped it’s ‘petals’, or bracts as they are strictly called.
