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

The USDA zone info for Jefferson should be read to estimate when it's possible to plant helianthemum.

Planting Calendar for Helianthemum

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

Helianthemum do well in moderate cold which means that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant helianthemum in Jefferson 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. If you wait any later than that and your helianthemum may not have a chance to fully mature. If you are starting your helianthemum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Jefferson. In the coldest months of winter you should expect an average low temperature of 10°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Jefferson and it is different every year. Since half of the time in Jefferson there is a last frost after March 15 be ready to protect your helianthemum if you have a late frost.

USDA Zone Info for Jefferson

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Jefferson

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