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.

A common way of determining when it's the best time to plant helianthemum is to consult the USDA zone info for Cedar Rapids.

Planting Calendar for Helianthemum

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

Helianthemum are moderately cold tolerant which tells us that you can start planting them earlier than other frost tender plants.

The earliest that you can plant helianthemum in Cedar Rapids 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

In Cedar Rapids the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -20°F.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Cedar Rapids and it will vary from year to year. Since half of the time in Cedar Rapids last frost occurs after April 15 be ready to cover your helianthemum if you have a surprise late frost.

USDA Zone Info for Cedar Rapids

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Cedar Rapids

You may be interested in your other planting guides for Cedar Rapids.