One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By reviewing the USDA zone info for Clay you should be able to estimate when 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.

Since helianthemum do well in moderate cold you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant helianthemum in Clay 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. 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

In Clay the average date of last frost happens on April 15. You should expect an average low temperature of 5°F in 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 Clay and it changes from year to year. Half of the time in Clay you get a frost after April 15 so just be sure to be ready to cover your helianthemum in the event of a surprise late frost.

USDA Zone Info for Clay

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 Clay

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