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.

By reviewing the USDA zone info for Plymouth it's a good idea to figure out when it's the best time to plant catharanthus.

Planting Calendar for Catharanthus

Frost tolerance for catharanthus:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since catharanthus do not do well in cold weather it is important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant catharanthus in Plymouth 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. If you wait any later than that and your catharanthus may not have a chance to really do well. If you are starting your catharanthus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Plymouth the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

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 Plymouth and it changes from year to year. Since half of the time in Plymouth it frosts late in the year after April 15 be ready to cover your catharanthus if you have a surprise late frost.

USDA Zone Info for Plymouth

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Plymouth

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