One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to estimate when it's the best time to plant calliopsis by referring to the USDA zone info for Leominster.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You can not plant calliopsis until after all chance of frost has passed because they require warm weather.

The earliest that you can plant calliopsis 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 calliopsis and expect a good harvest is probably August. Any later than that and your calliopsis may not have a chance to grow to maturity. If you are starting your calliopsis indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Leominster and it will vary from year to year. Half of the time in Leominster you get surprised by a frost after April 15 so just be sure to be ready to cover your calliopsis in the event of a late frost.

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.