Extreme low winter temperature is a major factor when choosing landscape plants. If you choose plants that aren’t cold hardy enough for your location they will not perform as expected, can become injured from cold, and can die as a result of the extreme cold temperatures. To help farmers and gardeners make decisions about what to plant in their areas, the USDA has established hardiness zones that are mapped on the USDA Hardiness Zone Map (See the website Planthardiness.ars.usda.gov for an interactive map to determine what zone your garden is in). 

The hardiness zones are determined by the average minimum winter temperatures in an area. There are 13 zones in 10 degree increments which are further divided into 5 degree increments noted by an “a” or “b” within each zone. New York hardiness zones range from 7b in Long Island with minimum temps from 5 to 10˚ to 3b in the elevations of the Adirondack Mountains with minimum temperatures -35 to -30˚. The lower the number of the zone the colder the minimum winter temperatures are. 

On most labels for perennials and nursery stock, the coldest hardiness zone that a plant can survive in is listed. If you are planting in a zone with a higher number, you are planting into a warmer zone so the plant shouldn’t be negatively affected by the area’s lowest minimum temperatures. For example, if the label of a perennial plant says it will survive in Zone 3, then you are safe to plant in Zone 3 and higher, such as Zone 5. If you suspect that you live in an area that tends to be colder than surrounding areas, play it safe and choose plants that will survive in a zone colder. This is a guide intended to help you determine what plants will thrive in your garden. 

Hardiness Zones of local towns and cities

• Syracuse, Baldwinsville, Camillus, Onondaga, Fayetteville, Bridgeport – Zone 5b (-15˚ to -10˚F)
• Cortland, Pompey, Cazenovia, Central Square, – Zone 5a (-20˚ to -15˚F)
• Oswego – Zone 5b (-15˚ to -10˚F) to 6a (-10˚ to -5˚F) depending upon proximity to Lake Ontario
• Watertown – Zone 4b (-25˚ to -20˚F)
• Rochester – Zone 6a (-10˚ to -5˚F) to 6b (-5˚ to 0˚F)
• Utica – 4b (-25˚ to -20˚F) to 5a (-20˚ to -15˚F)
• Old Forge – Zone 3b (-35˚ to -30˚F)

Cold damage

• Branches die back, sometimes looking black such as on roses. Evergreens may turn brown in spring. 
• Deciduous plants may not break dormancy or break dormancy very late. Perennials may not start growing from the crown or are much smaller than the previous year.
• Flower buds may freeze, reducing flowers and fruit production the following growing season.

Factors that may affect your Hardiness Zone relative to surrounding areas in CNY

• Higher elevations, such as the Adirondacks and hills south of Syracuse, have lower minimum winter temperatures
• Windchills from extreme winter winds don’t affect minimum winter temperatures. Plants are generally at the ambient temperature so wind passing over them doesn’t decrease temperature by removing heat as it would with, for example, the skin of a person. In fact, wind can help increase minimum temps by mixing colder air that has settled in low spots such as in a valley.
• Closer proximity to larger lakes such as Lake Ontario, Oneida Lake, and the Finger Lakes will increase minimum winter temps making those areas warmer
• There are areas north of Syracuse where zones change from warmer by Lake Ontario (Zone 6a) to much colder in the Tug Hill Plateau (3b) within 40 miles. It’s important to understand and know your hardiness zone before you plant into these areas.

Cold Zone Plants

Please note: This list does not imply the availability of items listed at any given time. For many Genera and species of plants, the cold hardiness will vary for specific cultivars and hybrids. Make sure to check cold hardiness for specific cultivars and hybrids. This list contains plants for certain zones as a guide. We cannot guarantee hardiness since we have no control over the climate or conditions in which the plant will be installed. In addition, when researching plants for hardiness, often zones listed for a specific plant vary depending upon the resource. Again, this is a guide to help customers make decisions. 

If you would like to download a copy of this guide please click here.