The USDA Zone info is a great tool for gardeners to help us determine your gardening 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 getting a good idea when it's the best time to plant helianthemum is to check out the USDA zone info for Cedar Falls.

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 more sensitive plants.

The earliest that you can plant helianthemum in Cedar Falls 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. 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

The average date of last frost is April 15 in Cedar Falls. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Cedar Falls is an average the actual date of last frost changes from year to year. Since half of the time in Cedar Falls it frosts late in the year after April 15 be ready to protect your helianthemum in the event of one of those late frosts.

USDA Zone Info for Cedar Falls

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 Falls

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