It is not harmful as long as you don't drive the total dissolved solids of the fertilizer solution past safe levels. If you don't know the TDS of your tap water then be cautious and use only 1/4 strength fertilizer and maybe 1/8 tsp of Epsom salts per gallon of water.

If the problem with your plants is an unhealthy root system then using fertilizers etc will not help revive them. Perhaps taking cuttings and rooting them would be a better option. Are the plants still looking dehydrated?

Using on your healthy Hoyas will cause no problems at all. Fertilizing and using Epsom salts etc on a Hoya with a damaged root system can easily do more harm than good as the chemical salts will quickly build up in the potting mix.

Is it possible for you to show us photos of the sick plants? A good close up of the leaves would help us decide just how stressed the plants are.

Mike

The macrophylla variegated has died. The roots look okay but when I attempted to take cuttings, the woody part was black inside which I assume is rot. The finlaysonii's leaves are a healthy shade of green but are soft and I believe should be hard and the Clandistina is the same way (I'm sure that is a member of the macrophylla family and should have hard leaves). I don't know what sort of scam this person is running but she has more hoyas up for sale this week. How could hoyas look like this after 2 days of traveling even if she did not ship them in a pot?

I can't find the charger to my digital camera so I can't post pictures right now.

Thank you.
Susan

If the leaves were not fully mature they would not be hard. Can you take photos as it would really help?
Shipping a plant that is in wet potting mix in the heat of the summer can cause problems. Were the plants wrapped in plastic or anything similar?

Mike

I should add that this is just my experience and everyone should judge a seller for themselves with what they receive.

Susan

Oh, we must have been sending at the same time.

They were shipping with a paper towel around the roots. The paper towel was dry.

Even if the paper towel was dry but was wet at first, I still don't think would cause the problem???

Susan

If you look at a picture, you would see healthy looking leaves and I do not believe they are new leaves (as I know what you're talking about).

Susan

So they were sent as bare root plants? I truly think you should reroot because it sounds like the roots are most likely dead. If the roots are dead nothing you do will revive them. If the roots are just stressed you need to put the plants into a hugh humidity environment like you would new cuttings.

One more question. If the leaves are healthy what causes you to think that the plants are stressed?

Mike

I'm trying to think of a hoya leaf to compare what the macrophylla was like when I opened the box, I would say soft like an australis leaf (didn't look healthy, tho) just dehydrated.

I'm only dealt with a dehydrated leaves situation once and that was a H Carnosa White leaf. I cut that whole plant up for cuttings and all are doing well but the leaves weren't as far gone as the macrophylla.

Susan