Ask Mr. Smarty Plants

Well, this is a tough one. The mission of the Lady Bird Johnson Wildflower Center is to promote the sustainable use and conservation of native wildflowers, plants and landscapes.  That means that we can only recommend plants that are native to your area and have evolved in and adapted to the natural conditions in your area prior to European settlement.

That is a roundabout way of saying there are no trees native to NYC that are really adapted to life in a container in full sun and the stresses associated with it. 

You will probably have to contact a nursery professional experienced with large container planting and you should look at examples around you in the city to see what plants are doing well in containers.

That being said, you really should be considering a large shrub instead of a small tree.  Most trees bloom in the spring but shrubs tend to bloom in the summertime and there are quite a few shrubs that can attain a significant size.  They can also be pruned to be quite attractive in a container.  When you do make a selection, you will need to consider winter root hardiness and select a shrub that will survive in at least one USDA Zone colder than yours.  That is because in the wintertime, the air is actually significantly colder that the soil.

Our Native Plant Database will generate a list of plants that are native to New York.  Do a Combination Search selecting: New York/shrub/sun/dry conditions and 6-12 ft size and it generates a list of 17 plants.  If you think you can keep the container moist, your choices will be broader with 26 to choose from.

The only plant from those lists that might be remotely interesting as a container plant is:

Physocarpus opulifolius (Atlantic ninebark)

It flowers in the summertime, the seedpods are a colorful red and remain on the plant for an extended period and it turns yellow in the fall.  There are cultivated varieties that offer variation in leaf color and red fall color.

You might also have luck with small, tough northern trees like

Betula nigra (River birch)

It will survive in a container (and not attain its maximum size), but does not meet your requirement of summer flowers.

I am sorry we could not give you the answer you were looking for.  Again, we encourage you to seek advice from local landscape professionals.

Physocarpus opulifolius

Physocarpus opulifolius

Physocarpus opulifolius

Betula nigra

Betula nigra

Betula nigra