what's happening to my plants?

[romy]

Hello,

this is my first time posting here and I need help.
I live in Phoenix, AZ and I have two plants of hibiscus in ground.

They were already here when I bought the house...in the beginning there were 3 plants, but last year, after a bad frost, I lost one of them.

I cut down a little bit the two I had left and they seemed to be recovering last summer, but now they are doing as worse as ever!
Except for winter months, I've been fertilizing them with the fertilizer bought on this website (17-5-24) once a month and I've been conditioning the soil with a soil acidifier once every other month.
what is wrong with them?

here some pictures:

PLANT 1



DETAILS OF PLANT 1




PLANT 2



DETAILS OF PLANT 2

[Darkhorse]

Hi Romy,

   From your photos it looks like it's too cold outside for your plants.  The first couple of pictures also make me think chlorosis, which means the plant needs fertilizer.  I've heard people say don't fertilize in winter.  I don't find this to be true.  Hibiscus like even feedings, and in winter the fact that you're watering less often (or should be, anyway) mean that you're feeding them less often by default as well. 

   What are the nighttime lows in your area?  I'm seeing this sort of damage (minus the chlorotic look--  yellowish leaves with darker green veins) on my plants in my cold greenhouse.

   Interestingly, your second plant looks to have incurred some salt burn (too much fertilizer).  My guess is that the crunchy edges on the leaves remain from this past summer.  Would you happen to remember whether or not this is true?

   So...  basically what I'm seeing is a combo of too cold plus improper fertilizing.  I've only been growing for a few years, so I'm sure others can elaborate.    Good luck with them, and welcome to the forum.

[Charlie]

Pretty good, Jordan. I will only add that in addition to a balanced fertilizer like HVH 17-5-24 they could also benefit and green up faster if you apply some chelated iron and epson salts.

Charlie

[romy]

thank you for your help Darkhorse and Charlie!

   From your photos it looks like it's too cold outside for your plants. 
   What are the nighttime lows in your area?  I'm seeing this sort of damage (minus the chlorotic look--  yellowish leaves with darker green veins) on my plants in my cold greenhouse.

this past winter temperatures were not that bad actually.... we arrived at freezing only once in December and the rest of winter we had lows of 39F, with an average temperature of 43F.

Do you think that these temperatures are too low for the plant? I am not an expert as you can tell 

 

   Interestingly, your second plant looks to have incurred some salt burn (too much fertilizer).  My guess is that the crunchy edges on the leaves remain from this past summer.  Would you happen to remember whether or not this is true?

Actually this plant was growing very well until February when I started realizing the change in color of the leaves....

do you guys suggest I should prune them down a little bit? especially the first one? or should i just leave them like that?

[Charlie]

Yes, I would prune them. Hibiscus grow back quickly and it's common for the plant to look much fuller and much better once they do grow back. But, if there is an underlying problem such as poor soil or very high pH the plant will still show the effects as it tries to grow back. Winter cold, even if there is little freezing, is hard on hibiscus and can cause a variety of problems that correct themselves once the temperature warms up again. Phoenix has a challenging climate and in some areas water quality and soil quality are not great either. The Phoenix Master Gardeners group is knowledgeable and several of its members know about growing hibiscus in that unique environment.

Charlie

[romy]

Thank you Charlie! I was actually wondering if it might be a problen with the soil...i didn't use any ground acidifier during the winter...coud that be part of the problem?