Answer: There are several considerations to consider. Based on your description I am not certain if your garden space is at ground level or up on a roof or balcony.
If it is elevated, it may be very windy thus causing your plants to dry out faster than they would in the ground. Windy exposures can also increase winter cold damage to plants. And, winter hardiness itself is an issue since plant roots are not as insulated as they would be in the ground. You may also have weight restrictions -- wet soil is extremely heavy. You may want to install a watering system as in summer watering may be needed twice a day.
In the US, plants are assigned a US Dept. of Agriculture (USDA) winter hardiness zone. The rule of thumb is to select plants rated at least a zone colder than your zone if you want to plant in containers. Your zip code places you in zone 6, so you might look for plants rated hardy to at least zone 5 (or a lower number) if you are working with containers.
Shade loving perennial plants to consider might include hostas and ferns (NYC tends to be humid in summer) along with interesting patterned ivies (Hedera helix). Annuals would include impatiens, nicotiana, coleus, perilla, begonias of all sorts. You could also try some non-hardy "summer bulbs" such as caladium and taro for foliage interest -- they can be stored and saved to replant the following year if desired.
I hope this gives you some ideas. Enjoy your new garden!
Q&A Library Searching Tips