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.

In Jamestown you can estimate when it's the best time to plant helianthemum by looking at 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 tend to make it in some cold which tells us that you can plant them a little bit earlier in the year than more sensitive plants.

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

The last month that you can plant helianthemum and expect a good harvest is probably August. 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

In Jamestown the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Jamestown and it is different every year. Since half of the time in Jamestown you get a frost after May 15 be ready to cover your helianthemum if you have a late frost.

USDA Zone Info for Jamestown

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Jamestown

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