One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By using the USDA zone info for Cambridge you should be able to determine when it's a good idea to plant ajuga.

Planting Calendar for Ajuga

Frost tolerance for ajuga:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Ajuga tend to make it in quite a bit of cold which tells us that you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant ajuga in Cambridge is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant ajuga and expect a good harvest is probably August. If you wait any later than that and your ajuga may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your ajuga indoors.

Last Frost Date

On average the last frost is on May 15 in Cambridge. It might get as low as -30°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Cambridge and it can change quite a bit from year to year. Half of the time in Cambridge it frosts late in the year after May 15 so make sure that you are prepared to protect your ajuga in the event of a late frost.

USDA Zone Info for Cambridge

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Cambridge

You may be interested in your other planting guides for Cambridge.