The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Charlestown you can figure out when you can plant helianthemum by using the USDA zone info.

Planting Calendar for Helianthemum

Frost tolerance for helianthemum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Helianthemum do ok in moderate cold which tells us that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

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

The last month that you can plant helianthemum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your helianthemum may not have a chance to really do well. Starting your helianthemum indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Charlestown. It might get as low as -5°F during the coldest months of winter.

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

USDA Zone Info for Charlestown

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 Charlestown

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