One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Boston you can figure out when you can plant catharanthus by checking out the USDA zone info.

Planting Calendar for Catharanthus

Frost tolerance for catharanthus:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You can not plant catharanthus until after all chance of frost has passed because they are not cold tolerant.

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

The last month that you can plant catharanthus and expect a good harvest is probably August. Any later than that and your catharanthus may not have a chance to fully mature. Starting your catharanthus indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Boston the average date of last frost happens on April 15. You should expect an average low temperature of -5°F in the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Boston and it can change quite a bit from year to year. Half of the time in Boston it frosts late in the year after April 15 so just be sure to be ready to protect your catharanthus in the event of one of those late frosts.

USDA Zone Info for Boston

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Boston

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