One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

The USDA zone info for Harper Woods 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 are moderately cold tolerant which tells us that you can plant them earlier than more sensitive plants.

The earliest that you can plant helianthemum in Harper Woods 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. If you are starting your helianthemum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Harper Woods the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Harper Woods is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Harper Woods you get a frost after April 15 be ready to protect your helianthemum in the event of a late frost.

USDA Zone Info for Harper Woods

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°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 0°F.

Plants to Grow in Harper Woods

You may be interested in your other planting guides for Harper Woods.