I'm lost and sad as I see my new Hypoestes phyllostachya dying and am desperate. I do not know what to do. I bought a week ago, and I brought from Japan to Barcelona. Survived perfectly the trip and 3 days in Barcelona in its own small pot, then yesterday morning I decided to join with other 3 small plant in a bigger pot. I added a bit of substrate and water, put it inside and after 6 to 10 hours become weak, with its steam and leaves down with not energy at all. I took out and back to its small pot, put it in a more shinny area, but still weak and even worse.. What is happening, what can I do? I've never seen a plant in less than a day become like that, like dying.. Temperature is 18-24 degrees C. and the ground is wet.
To large of a pot and excess watering likely are the reasons for you plants health.
Allow the soil to dry slightly between watering.
Your plant may or may not come back from the stress.
Time will tell.
Here is a link to refresh yourself on the care of a Polka Dot plant.
https://www.gardeningknowhow.com/houseplants/polka-dot-plant/growing-polka-dot-plants.htm
Is it toxic to cats?
The color looks washed out on most of the leaves. Some are ok, but the tips of some of the leaves are browning. I water once a week and mist daily. The plant growth itself is doing amazing and getting bushy. I heard browning tips mean too much sun and washed out color means too little sun.... so which is it if I have both as a problem?
Indirect bright light is best, you can sit the plant on a tray of pebbles with water for added humidity.
If your watering with conditioned water this can lead to build up of salts in the soil, allow the water to sit on the counter for 24 hours before using.
Make sure the plant is moist but not soggy.
Good growing conditions should improve your plants health and in turn show more color in the leaves.
https://www.gardeningknowhow.com/houseplants/polka-dot-plant/polka-dot-plant-propagation.htm
https://www.gardeningknowhow.com/houseplants/polka-dot-plant/growing-polka-dot-plants.htm
The leaves fell off, but when I pull out the leaves, I find white stuff on all the stems. The fuzz is still there after putting water on them. I don't know what I can give it.
You may be overwatering your plant.
The soil should be moist but well draining. Make sure the container has a drainage hold; so excess moisture can drain from the soil.
If you are seeing actual mold on the surface or the plant, your plant may not recover.
Remove the dead plant material. Wait to see if any new growth appears.
Here is a link to refresh you on the care requirements.
https://www.gardeningknowhow.com/houseplants/polka-dot-plant/growing-polka-dot-plants.htm
I have several polka dot plants that are almost finishing their flowering run. the stems are leggy and I am wondering if its ok to prune back the excess growth and let them thicken up or should i wait until they have finished flowering.
This article will help you.
https://www.gardeningknowhow.com/houseplants/polka-dot-plant/growing-polka-dot-plants.htm
I have 3 varieties in my kitchen and they seem quite happy, but I would like to know how high they grow, as I am having to prop them up. Should I cut them back, and if so, how far?
They will, typically, grow to a height of 3 foot tall. They are usually compact, so it there is a lot of space between each leaf on the stem then this can be a sign that it is lacking light.
This link will take you to a page with more information on the care of these: https://www.gardenanalyst.com/ornamental/shrubs/polka-dot-plant-care-guide/
I have read that these are perennials. Mine have been left outside (Oklahoma) this winter. They are in pots, will they come back in the spring? It has already been below freezing and faced frigid temperatures.
They don't usually survive temperatures that low for very long. They are perennials as houseplants, and where the temperature never gets below freezing. You will have to move them inside, and there is a possibility that they will recover.
This article will give you more information about the plant: https://www.gardeningknowhow.com/houseplants/polka-dot-plant/growing-polka-dot-plants.htm