I have a holly plant which is currently in a planting pot at the moment. It's about a foot and half tall. I was wondering when is a good time to plant such a plant and how long it should be left in the container before I can plant it?
Certified GKH Gardening Expert
As long as it is not too cold where you are located, you can go ahead and put it in the ground now. However, for most regions it's a bit too cool for planting so I would hold off until spring. As long as the plant is not too large for the container it's currently in and if you keep it located in a sheltered location, the shrub should be fine as is for spring planting.
Though hollies are quite hardy, should you expect unusually cold weather conditions, you may want to give it some added protection (since container plants tend to be more susceptible to cold) by insulating the pot with bubble wrap (or something similar). Also, make sure that it does not dry out completely. It should receive adequate moisture through winter precip, but if it hasn't rained (or snowed) in awhile, give it some water at least once or twice monthly. For more info on caring for hollies once planted, this article will help: https://www.gardeningknowhow.com/ornamental/shrubs/holly/growing-holly-bushes.htm