My hibiscus plant used to give really big and yellow (dark pinkish almost magenta shade in centre) flowers but after a month the leaves began to curl inwards and the buds started to fall off before blooming.. i removed all the leaves and thought id let new healthy leaves grow back. I can see new growth but the flower size has reduced immensely. They're much lighter in color too. The first picture is when bought it and in the second picture.. that's how it is now. I gave it some DAP and compost two weeks ago. Please let me know whats going wrong with it.
You don't say how long you've had the plant in the pot, but these are large shrubs - being constrained within a pot is likely the problem, because it restricts root space, and a plant can only grow as well as its roots allow. Yours appears to be a variety of HIbiscus rosa-sinensis, and the average height and spread for these (in the ground) is between 8-15 feet tall by 5-8 feet wide, but in order to achieve this and remain healthy, the plant needs to grow and spread its roots. Smaller flowers can also be a signal of reduced root space. I can't otherwise see any infection/infestation problems from the images you've provided, though if its been in the pot a while, a shortage of nutrients might also be an issue, a problem that is also resolved by planting in the ground, when the plant is able to seek out for itself what it needs. Some clarification of what 'DAP' is might be helpful, along with what type of compost you added, as well as knowing how long it's been in the pot and what fertilizers you've used in the meantime, but it doesn't look like its dying, it just has the look of a plant that may be restricted at the root or is suffering environmental/care problems. Temperatures wherever you are might be having an impact too, so knowing where you are would also be useful; I'm also curious about the white 'flakes' present at soil level in the first image...
Hey. By DAP i mean di ammonium phosphate. The white flakes that you see are crushed egg shells. I thought they'd be helpful in some way. The compost that i added is neem(azadirachta indica) organic manure mixture along with vermicompost. I bought this from a nearby nursery. Also, I'm from india where the temperatures are usually moderate. Can you also tell me about the leaf curling problem? Is it also because of limited space? It's been around 3 months since i got it. Thanks a lot. Dec 26, 2018 at 13:41
Okay, better not to use DAP - you need a balanced fertilizer with an NPK readout of something like 10-10-10 rather than a high phosphate one. DAP is also not great to use in potted plants either, and might be responsible for leaf curl - there's also a fair amount of defoliation (leaf loss) visible. I know where you are its difficult to find sterilized potting soil, & its common for manure based products to be added to pots, but the general rule is, manure should not be used in pots because of possible pathogens (which are fine in open ground) and may burn roots, tho cow manure usually okay– BambooDec 26, 2018 at 13:59
Oh okay. I'm gonna move the plant into ground asap. About the leaf loss, i on purpose removed the older ones thinking there will be new healthy growth with no curling (I'm a beginner in gardening). But the new ones seem to be curling as well. There's an excessive amount of bud dropping. The buds which manage to grow look dull. I hope it grows good again when in open ground. Thanks a lot. Dec 26, 2018 at 14:11
You could certainly dig over an area and add some manure prior to planting it out... that would improve the conditions for the plant too– BambooDec 26, 2018 at 16:48
I was searching on hibiscus and came across this post and thought it would be worthwhile to add my experience with potted hibiscus. The objective is for people living in apartments and having potted hibiscus to continue enjoy their plants and not assume that hibiscus don't do well in pots.You can see the pic of my plant here Hibiscus flowering is not really dependent on pots. If the roots are constricted, then just repot the plant after trimming roots. I am successfully growing large hibiscus flowers in pots without much special care. There are a lot of interesting videos on hibiscus in pots on youtube, do have a look.
Not everyone has the luxury of having a outdoor garden , if u live in an apartment, repot the plant after a year.
I am also facing a similar issue of small flowers on one of my plants. Have repotted and pruned for two weeks now. Will see results after a month or two
As for leaf curling and bud drop, adding compost or vermicast have worked for me most of the time.
Check soil acidity. Hibiscus like acidic soil.
Lastly make sure you plant gets enough sunlight and you are not over watering.