Frangipani do not like to be fussed over, they prefer to be slightly drier and not watered constantly or they will rot, they also like to have a feed during the growing season but otherwise left alone. While dormant throughout winter & while no leaves are on them it is best to not water them unless they start to "prune up" which is when they are feeding on themselves, if this happens then you need to give them a very small amount of water over a few days until it disappears.
It is a good to feed them a slow release fertilizer at the start of spring & summer, the NPK needs to be fairly even as if it is too nitrogen(N) rich then it only promotes leaf & root growth, for flower development & health you need a higher P:K ratio with a lower N, orchid bloom food or most fruiting/flowering fertilizers are usually a good NPK mix to promote this. If your frangipani are in pots you will need to water more often once they leaf up, during summer this can be several times a week(even daily), mornings are the best time to water, water when the mix is dry when you insert your finger or the pot is light(leaves will hang down). An in ground plant can be watered less often as the soil maintains more moisture than a pot. If your frangipani are in a hot house then it is also a good idea to mist the air so that you maintain a higher humidity which they love. Frangipani also require a minimum of 6 hours sun a day, the more the better as it is needed to promote growth & flowering, if they are too shaded they will not flower properly if at all and have very small flowers & inflo's. Their growth will also be spindly which leads to a lot of damage in winds etc. We use Organic Xtra at the farm, it is pelletized and contains chook poo, fish emulsion, seaweed, blood and bone etc, Dynamic Lifter Plus is very similar.
If in pots it is advisable to make sure they are not top heavy with the pot large enough to balance the plant otherwise they will continually fall over in winds. Once a plant is around a metre tall it should be strong enough to be put in the ground in most Australian states, in the colder ones just make sure it is in a protected area if frost are common. If you are going to put your plants into a bigger pot it is advisable to do this at the start of spring when the frangi has started to claw and has flowing sap, they will really take off after being potted up & fed.
You also need to be mindful of having stakes set for the plants as well, even in pots they need support. Those in the ground need to be staked as well, if there are heavily leaf laden branches it is advisable to stake them also as if the folliage gets wet and then there are winds these branches are very susceptible to snapping under the extra weight/pressure, I have seen a lot of nice trees ruined with this happening. I also recommend trimming the amount of leaf on the trees so that they are not just covered in it, this also leads to fungal problems in the more humid states.
Basically there are just a few golden rules for frangipani:
1. Do not over water, only when dry(not at all when dormant)
2. Feed them during their growing season(not a high N).
3. Make sure they have at least 6 hours of sun a day, more if possible.
4. Remember the branches are not very solid so do not put any excess stress on them.
5. Do not let them get too much leaf coverage so that they can maintain good air circulation.
6. When transplanting always water in with seasol or similar to help de-stress the plant.
7. Remember that what you do to your plant this season will reflect in its flowering/growth next season.
Follow these simple rules and you should have quality frangipani.