My uncle had a plant that he cut branches from in the late fall and brought them indoors and sometimes they developed these billowy white puffy seed heads that lasted all winter. He said it was a Monrovia or Mandevilla "Summmer Snow" bush, but I can't find anything about them turning into billowy puffy seed heads when brought indoors in the winter. Do you know of any bushes that will do that?
Forcing branches is a fun practice and can give you lots of surprises! I can't verify the type of shrub that you are referencing, but often Clematis vines have an interesting seed head after flowering.
https://www.gardeningknowhow.com/ornamental/shrubs/shgen/forcing-shrubs-to-bloom.htm
https://www.gardeningknowhow.com/ornamental/vines/clematis/growing-clematis.htm
I think it is dipledenia
All those these are two different shrubs, the care for them is quite similar. This article will help you to tell the difference between them, and care for them: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-a-dipladenia.htm
When is the best time to re-pot my Mandavilla? It is 5 ft tall and I winter it in my garage with a grow light and if needed plant heat mats.
Spring would be best to repot your plant.
Leave it in it's existing pot to overwinter.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/winterizing-mandevillas.htm
For a mandevilla that is still quite small, work your way gradually up to that size, by moving it to a pot 2 inches larger every time its roots begin to protrude from the drainage holes of the old one. Plants grown in containers that are too big for them are much more likely to contract root rot than those in tight quarters. Make sure the pot has adequate drainage holes.
#1 question is plant or any parts of it harmful to cats? #2 Can I grow rosemary in the same pots as the Mandevilla and will that help keep the cats out. The Mandevilla were recently taken inside for the winter.
It isn't on any lists of toxic plants for cats, according to my research. It is always best to try and keep pets from getting into plants that you don't know about, but in this case, it won't harm cats in any way.
I have a potted mandevillia on my deck all summer,and would like to bring it in for the winter(zone 7)How should I care for it inside?
These articles will help you.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/winterizing-mandevillas.htm
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-mandevilla-indoors.htm
WILL THE CATERPILLARS BECOME BUTTERFLIES? ARE THEY DEADLY PESTS?
Can you upload some images?
You can also check with your County Extension Office for an id.
This plant was outside however we had a few days of heavy rain I bagged it whe I saw the leaves turning and brought it in the house
Can you include a photo? Depending on what kind of material was used to bag it, this may have led to further infection. A photo will help me to see the damage, and if it can be cured.
For now, this article will help you with the care of these: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm