Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of getting a good idea when it's the best time to plant catharanthus is to refer to the USDA zone info for Leominster.

Planting Calendar for Catharanthus

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

Since catharanthus require warm weather it's necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant catharanthus in Leominster 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 really do well. If you are starting your catharanthus indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Leominster is not always accurate the actual date of last frost changes from year to year. Since half of the time in Leominster you get surprised by a frost after April 15 be ready to cover your catharanthus if you have one of those late frosts.

USDA Zone Info for Leominster

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Leominster

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