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

By reviewing the USDA zone info for Joliet you should be able 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.

You can plant helianthemum a little bit earlier in the year because they do well in moderate cold.

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

Last Frost Date

On average the last frost is on April 15 in Joliet. You can expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Joliet is just an average and the actual date of last frost is different every year. Half of the time in Joliet you get a frost after April 15 so be sure to be ready to cover your helianthemum in the event of a surprise late frost.

USDA Zone Info for Joliet

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Joliet

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