Hibiscus yellow leaves problem

[Usama]

Leaves are turning yellow and then falling off. As shown in the first two images.

1434656218096.jpg [attachment][attachment=1]1434656398939.jpg

[Usama]

Pardon me. The leaves are bad only in the last two images. First one is a healthy plant right next to the damaged one.

[Izhar]

over watering may be the cause..

[Usama]

I water cautiously. There are two Hibiscus plants in the same bed. Both get same amount of water. The other one is fine

[Izhar]

Are both same varieties?? increase yellowing of leaves shows that plant's roots are unable to absorb the nutrients from the soil which can be due to:

1) Roots are diseased due to overwatering or fungal problem
2) pH problem

[Muhammad Arif Khan]

Izhar, I have observed the same in some Hibiscus plants, please note that it is random and not age related, only one or two leaves on a branch are affected others are healthy. Could it be some infestation ?

[Izhar]

Sir, this is micronutrient deficiency (unavailability will be more appropriate)... most probably iron if the newly formed leaves are yellowing and magnesium if the older leaves are yellowing...

I have observed that some varieties are more tolerant of bad conditions..

One more and very important thing... hibiscus dont like phosphate fertilizer at all.. their requirement for phosphorus is very little..

[Usama]

Sir, this is micronutrient deficiency (unavailability will be more appropriate)... most probably iron if the newly formed leaves are yellowing and magnesium if the older leaves are yellowing...

I have observed that some varieties are more tolerant of bad conditions..

One more and very important thing... hibiscus dont like phosphate fertilizer at all.. their requirement for phosphorus is very little..

It is the older leaves that are falling off. And both varieties are different. I am grateful for you diagnosis.