Second photo

Top of leaf showing brown spots

Underside of leaf

Hi Sapphy, welcome to the forum. It looks like your spotty leaves may have a spider mite infestation. You can get rid of most sucking pests with neem oil or insecticidal soap.

The leaf with brown spots looks like it got sun scorched. These plants are from the tropics where they would get some soft cloud cover along with hot temps and high humidity. Mine here in Texas often get that scorched look in our cloudless summers.

Hi Jandey,
Thanks so much for replying to my post! I have since moved my plant to a more shady spot on the balcony where it is a little more protected from the western sun. I have also found a white oil product to spray on the leaves that apparently deals with mites and lots of other nasties. Hopefully my frangipani will be happy now and maybe give me some flowers!
Thanks again!

Hi all!
My plant is still not happy!
As I said before, I have sprayed both front and back of the leaves with a white oil petroleum oil product. I thought I put a bit much on so I wiped off the excess. I also gave the plant 1.5 small handfuls of slow release fertilizer (see attached photos for info), I watered the plant and all seemed fine. This was a few days ago. Today I went out to check on it, and some of the leaves now have black, withered tips. I have pulled off the sickest looking leaves (see photos) Could this be from the fertilizer? I have not fertilised it since last summer. It has had no fertilizer at all in the last year. It had the same fertiliser last year and was ok. It is in a fairly large pot- 1.5 feet. The fertilizer packet says 5 tablespoons, I don't think I used this much even. Any help would be awesome. I am worried about my plant!
Stay tuned for more photos.
Thanks

Your plant does look like it has a mite or thrip problem, and photo-oxidation (sunburn) might be an explanation for the large brown areas, but the fact there is significant browning on the margins of the leaves makes me think it might be attributable to one or more of several other possibilities.

First, if you are to do a good job at fertilizing, you have 2 important considerations. You have to make sure your plant has all the individual nutrients it normally takes from the soil available in a concentration high enough to ensure there aren't any deficiencies, without the concentration being so high that it actually inhibits water (and the nutrients dissolved in that water) uptake. Something that complicates this issue is, everything that manages to become dissolved in the soil solution, whether the plant needs it or not, has to be considered because it increases the dissolved solids concentration of the soil solution and impacts the plant's ability to absorb water.

If you water only until you see a little water in the collection saucer, almost all of the minerals (salts) in your tap water + the fertilizer in your fertilizer solutions is accumulating in your soil. It's a distinct possibility that your plant is suffering from a lack of water, even if you keep the soil wet.

Which brings us to keeping the soil wet. Water and nutrient uptake is an energy-driven process. The plant needs plenty of O2 in the root zone to burn (oxidize) the plant food (sugar/carbohydrate) to create the energy that drives the process. W/o sufficient air in the root zone, the plant can't take up water or nutrients efficiently, and the leaf tissues die due to dehydration. So, too high a concentration of dissolved solids (salts) in the soil causes a drought response and spoiled/shedding foliage. Strangely, too much water in the soil (from over-watering, or more frequently a poor soil) also causes a drought response due to lack of O2. Your plant can die of thirst in a sea of plenty.

While plants lose foliage due to natural senescence (aging), root-bound conditions is a prime cause of leaves being shed. If your plant hasn't been repotted or potted up (there is a big difference between the two) in the 3 years you've owned it, you can be assured that root congestion is playing a big part in the appearance and vitality of your plant. For best vitality, plants should be potted up BEFORE the root/soil mass can be lifted from the pot intact. If they are allowed to get to that point, potting up will only partially restore a plant's ability to grow to its potential. IOW - once a plant is allowed to become severely root bound, it will be permanently limited, even if it was planted out (in the ground) at some point, unless the root issues were addressed during a repotting session or the plant was root pruned to correct root issues before planting out.

The 3 issues likely to have the greatest impact on your ability to consistently provide conditions that allow your plant to realize as much of its genetic potential as possible are A) a soil that allows you to water correctly w/o having to worry that your soil will remain soggy so long it affects root function (due to lack of O2) or root health (as in root rot) B) the right light C) a fertilizer program that suits the plant's needs - so there are no nutrient deficiencies or excesses. Many things have the potential to severely limit your plants, but you'll make the most forward progress if you concentrate on optimizing cultural conditions in these areas.

A plant is like a spinning top. Everything runs smoothly until one of the plant's systems becomes unbalanced, which sets the top to wobbling. If the wobble isn't corrected, it affects other systems and just gets worse, until eventually the top stops spinning. The best growers are those who are able to identify and eliminate the things that are limiting their plants before the top starts to wobble. These observations aren't plant specific - they can be applied to everything we grow in containers.

If there is anything specific you'd like to ask .....

Al