|I live 20 miles north of NYC. What columnar trees can I put in containers to flank my front door? The door faces west and is recipient of heavy winds in the winter. Seasonal sun ranges from 5 to 8 hours a day|
|You could try an upright juniper such as Sky Rocket. Junipers will tolerate hot sun and wind fairly well and are reliable, sturdy plants when planted in the ground. They also prefer a well drained soil which helps them adapt to container culture under home conditions. The larger the container, the better your chance of success.
I should mention however that it is very difficult to overwinter evergreens successfully in containers in an area such as yours with extended cold winter weather. The root system is stressed due to the limited root space and lack of insulation from both extreme cold as well as oscillating temperatures. The plants are subject to drying out once the soil freezes and the heat reflecting off the house and walk increases the stress even more. The combined stresses typically take their toll by spring or early the next summer and they need to be replaced. I'm sorry I can't be more encouraging.