Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of making a decision about when you can plant helianthemum is to refer to the USDA zone info for Commerce.

Planting Calendar for Helianthemum

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

Helianthemum can survive in moderate cold which tells us that you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant helianthemum in Commerce 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 grow to maturity. Starting your helianthemum indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Commerce the average date of last frost happens on March 15. You can expect an average low temperature of 10°F in the coldest months of winter.

It's important to remember that USDA zone info for Commerce is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Commerce you get surprised by a frost after March 15 be ready to cover your helianthemum in the event of a surprise late frost.

USDA Zone Info for Commerce

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 Commerce

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