One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of determining when it's the best time to plant helianthemum is to refer to the USDA zone info for Zone 2a.

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 are moderately cold tolerant.

The earliest that you can plant helianthemum in Zone 2a is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant helianthemum and expect a good harvest is probably August. If you wait any later than that and your helianthemum may not have a chance to grow to maturity. You can get started a little bit earlier by starting your helianthemum indoors.

Last Frost Date

In Zone 2a the average date of last frost happens on May 15. You can expect an average low temperature of -50°F in the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Zone 2a and it is different every year. Half of the time in Zone 2a you get a frost after May 15 so always be ready to cover your helianthemum if you have a surprise late frost.

USDA Zone Info for Zone 2a

Here is the info for USDA Zone 2a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	August 15
Lowest Expected Low	-50°F
Highest Expected Low	-45°F

This means that on a really cold year, the coldest it will get is -50°F. On most years you should be prepared to experience lows near -45°F.

Plants to Grow in Zone 2a

You may be interested in your other planting guides for Zone 2a.