Before planting it is a good idea to find your USDA Zone info to figure out 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.

The USDA zone info for Smyrna should be reffered to in order to figure out when you can 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 can survive in mild cold which means that you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant helianthemum in Smyrna 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. Any later than that and your helianthemum may not have a chance to really do well. 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 the last frost is on April 15 in Smyrna. In the coldest months of winter you can expect an average low temperature of 5°F.

Since the USDA zone info for Smyrna is not always accurate the actual date of last frost will vary from year to year. Half of the time in Smyrna last frost occurs after April 15 so always be ready to protect your helianthemum in the event of a surprise late frost.

USDA Zone Info for Smyrna

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Smyrna

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