I have oleander trees in pots and in winter time I bring them indoors. When shall I bring them outdoors? I live in Long Island, N.Y.
The plants can be returned outdoors after danger of frost.
Exposure to cold will exfoliate the plants so use caution until temperatures are moderated.
Please remember that all parts of the plant are toxic and you should use protective gear when handling all parts of the plant.
Here is a link to refresh you on the care requirements.