When can I plant Helianthemum in Zone 1a

The USDA Zone info is a great tool for gardeners to help us determine our gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for our area.

You can determine when it's possible to plant helianthemum in Zone 1a by checking out the USDA zone info.


Planting Calendar for Helianthemum

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

Helianthemum are one of those plants that can tolerate a little bit of cold weather which tells us that you can get them planted earlier than other frost tender plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant helianthemum
Possibly ok, but a risky time to plant helianthemum
Probably not a good time to plant helianthemum

The earliest that you can plant helianthemum in Zone 1a is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant helianthemum and expect a good harvest is probably July. You probably don't want to wait any later than that or else your helianthemum may not have a chance to really do well. Starting your helianthemum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is June 15 in Zone 1a. We should expect an average low temperature of -60°F in the coldest months of winter.

Keep in mind that USDA zone info for Zone 1a is not always accurate and our actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 1a we get surprised by a frost after June 15 be ready to cover your helianthemum if we have a late frost.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)June 15
Average Date of First Frost (fall)July 15
Lowest Expected Low-60°F
Highest Expected Low-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in our other planting guides for Zone 1a.