Knowing your plant hardiness zone helps you to figure out what can survive the winter in your garden. Massachusetts is geographically diverse, so it covers several different plant zones.
So, what zone is Massachusetts for plants? Plant hardiness zones in Massachusetts include 5a, 5b, 6a, 6b, 7a, and 7b. Western Massachusetts includes plant hardiness zones 5a, 5b, and 6a, with temperatures down to -10 degrees Fahrenheit (-23 degrees Celsius) or lower. Eastern Massachusetts includes plant hardiness zones 6b, 7a, and 7b, where temperatures do not go below -5 degrees Fahrenheit (–21 degrees Celsius).
Of course, there are pockets of warmer or colder areas within some parts of the state. Microclimates in a given area also make a difference as far as how cold it gets.
In this article, we’ll talk about the plant hardiness zones in Massachusetts and in some of the major cities in the state. We’ll also discuss what the zones mean in terms of temperature and planting.
Let’s get started.
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What Zone Is Massachusetts For Plants?
The 6 plant hardiness zones in Massachusetts include everything from 5a (coldest temperature of -20 degrees Fahrenheit) to 7b (coldest temperature of 5 degrees Fahrenheit). This provides a vast range of climates in the state of Massachusetts.
Areas of Massachusetts close to the Atlantic Ocean (Cape Cod and the South Shore) tend to have warmer zones (Zones 6b, 7a, and 7b).
Areas in Western Massachusetts close to New Hampshire, Vermont, and New York tend to have cooler zones (Zones 5a, 5b, and 6a).
The following table gives the climate zones or temperature ranges, in degrees Fahrenheit (F) and degrees Celsius (C) for each of the 6 USDA plant hardiness zones found in Massachusetts.
| USDA Zone | Low Temp Range (F) | Low Temp Range (C) |
|---|---|---|
| 5a | -20 to -15 | -29 to -26 |
| 5b | -15 to -10 | -26 to -23 |
| 6a | -10 to -5 | -23 to -21 |
| 6b | -5 to 0 | -21 to -18 |
| 7a | 0 to 5 | -18 to -15 |
| 7b | 5 to 10 | -15 to -12 |
temperature ranges for Massachusetts.
Knowing your plant hardiness zone in Massachusetts helps you to figure out which plants can make it through winter in your area.
For example, according to Fast Growing Trees, Bing Cherry trees grow well outdoors in Zones 5 to 8. Since Massachusetts covers Zones 5a to 7b, Bing Cherry trees should be fine to survive the winter anywhere in Massachusetts.
On the other hand, Ponderosa Lemon trees grow well outdoors in Zones 9 to 11. That means there is nowhere in Massachusetts where you can grow them safely outdoors. They would need to live in a greenhouse or indoor facility and kept warmer than the outside air.
Plant Hardiness Zone History
- The very first map in 1938 (at Arnold Arboretum) had 8 zones.
- The first USDA Plant Hardiness Zone map came out in 1960, with 10 zones. Each zone was a “swath” or band of the country with 10 degree Fahrenheit differences in average annual minimum temperatures. Higher zones meant warmer minimum temperatures; for example, Florida might have areas with Zone 10, while parts of Vermont are Zone 4.
- The USDA updated their map in 1990, using 13 years of data from 1974 to 1986. This new map also included 5-degree bands (instead of the 10-degree bands from the earlier map). For example, 5b was slightly warmer than 5a.
- The USDA updated their map again in 2012, using 30 years of data from 1976 to 2005. This map uses 13 zones, and each has “a” and “b” subzones.
Microclimates
Remember that certain terrain features can affect the temperature in an area, including:
- Elevation (hills and valleys)
- Rocks & Hedges (wind reduction)
- Water (close to a lake or ocean)
According to the University of Massachusetts, a small area (such as a garden) can contain a microclimate. A microclimate might have minimum temperatures that are higher or lower than those in the surrounding area.
For example, a sunny garden location in Zone 6b (such as Boston) might allow plants that are rated for Zone 7a to survive. This is especially true if you keep the plants in a greenhouse, which can keep them several degrees warmer.
(You can learn more about how to protect plants from cold and frost on my resource page here).
On the other hand, an open area with a low elevation (where cold settles) in Boston could make it difficult to grow plants rated for Zone 6b.
A low-lying area in Western Massachusetts could easily dip below -20 degrees Fahrenheit (-29 degrees Celsius) in winter.
What Planting Zone Is Central Massachusetts?
Most of central Massachusetts falls into plant hardiness zones 5b or 6a. This means these areas have a minimum temperature of -15 degrees Fahrenheit (-26 degrees Celsius) for Zone 5b or a minimum temperature of -10 degrees Fahrenheit (-23 degrees Celsius) for Zone 6a.
Central Massachusetts includes the city of Worcester (the 2nd most populous city in the state).
What Planting Zone Is Worcester, MA?
Worcester, Massachusetts is in plant hardiness zones 5b and 6a. The growing season in Worcester is 167 days long (about 5.5 months).
Some southern parts of the city into the center of Worcester are in the colder Zone 5b, with a minimum temperature of -15 degrees Fahrenheit (-26 degrees Celsius).
The northern and eastern parts of the city, along with some parts of western Worcester, are in the warmer Zone 6a, with a minimum temperature of -10 degrees Fahrenheit (-23 degrees Celsius).
You can see a more detailed map of the plant hardiness zones in Worcester, Massachusetts on PlantMaps.
Of course, with its hilly terrain (including Mount Saint James at the College of the Holy Cross), Worcester is sure to have lots of different microclimates. This is especially true if you go to the trouble of creating your own microclimate!
Some of these microclimate areas could certainly dip below -15 degrees Fahrenheit in winter.
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What Planting Zone is Boston, MA?
Boston, Massachusetts is in plant hardiness zones 6b and 7a. The growing season in Boston is 206 days long (about 7 months), which is 39 days longer than Worcester’s growing season.
The western part of Boston (including the parts bordering Newton, Needham, Dedham, and Milton) is in the cooler Zone 6b, with a minimum temperature of -5 degrees Fahrenheit (-21 degrees Celsius).
The eastern part of Boston (closest to the Atlantic Ocean, including the parts bordering Chelsea, Revere, and Winthrop) is in the warmer Zone 7a, with a minimum temperature of 0 degrees Fahrenheit (-18 degrees Celsius).
You can see a more detailed map of the plant hardiness zones in Boston, Massachusetts on PlantMaps.
If you are landscaping in Zone 7, you might like to read my article on Zone 7 perennials.
Of course, Boston is much closer to the ocean than Worcester, and so it is much warmer on average. Boston also boasts a much longer growing season than Worcester.
If you live near the water and keep your plants in a greenhouse with proper cold protection, you might be able to keep plants alive outdoors in Boston that are rated for Zones 6a or colder.
What Planting Zone Is Plymouth, MA?
Plymouth, Massachusetts is in plant hardiness Zone 6b, with a minimum temperature of -5 degrees Fahrenheit (-21 degrees Celsius).
The city borders the Atlantic Ocean, making Plymouth’s minimum temperature higher than most of the rest of Massachusetts.
The growing season in Plymouth is 157 days long (about 5 months), which is 10 days shorter than Worcester’s growing season.
You can see a more detailed map of the plant hardiness zones in Boston, Massachusetts on PlantMaps.
The only parts of Massachusetts that are warmer than Plymouth are Cape Cod and a small area south of New Bedford, which are in plant hardiness zones 7a or 7b.
What Are The First & Last Frost Dates In Massachusetts?
It is also important to know the first and last frost dates for your location. This will help you to figure out things like:
- When to start seeds indoors
- When to plant seeds outdoors
- When to transplant outdoors
- When to cover plants to protect from frost (fall or spring)
Of course, the exact dates will depend on what you are planting. Some crops (like tomatoes) should be started from seed indoors and transplanted outdoors well after the last spring frost date.
Other crops (such as peas) can be planted directly in the soil outdoors, and they will survive in cool weather.
The table below gives dates for last spring frost and first fall frost in various cities in Massachusetts.
| City | Last Spring Frost Date | First Fall Frost Date |
|---|---|---|
| Boston | April 10 | November 3 |
| Brockton | May 8 | October 4 |
| Fall River | April 19 | October 30 |
| Lowell | May 6 | October 4 |
| Lynn | April 30 | October 9 |
| New Bedford | April 18 | October 25 |
| Pittsfield | May 14 | September 30 |
| Plymouth | May 6 | October 11 |
| Revere | April 10 | November 3 |
| Springfield | May 8 | October 2 |
| Worcester | April 28 | October 13 |
Conclusion
Now you know which plant hardiness zones are in Massachusetts. You also have a better idea of where the major cities fall, and what zone you live in.
If you are feeling adventurous, you can try growing pawpaw trees in your Massachusetts garden!
Looking for drought tolerant plants that grow in Massachusetts? Check these out!
I hope you found this article helpful. If so, please share it with someone who can use the information.
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~Jonathon