When to Plant Helianthemum in Zone 1b

One of the best tools that you have as gardeners to help us figure out 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.

It's possible to figure out when it's possible to plant helianthemum by reviewing the USDA zone info for Zone 1b.


Planting Calendar for Helianthemum

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

Since helianthemum are one of those plants that can tolerate a little bit of cold weather you can plant them a little earlier in the year than more sensitive 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 1b 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 fully mature. You can get started a little bit earlier by starting your helianthemum indoors.

Last Frost Date

In Zone 1b the average date of last frost happens on June 15. In the coldest months of winter you should expect an average low temperature of -55°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Zone 1b and it will vary from year to year. Half of the time in Zone 1b it frosts late in the year after June 15 so make sure that you are prepared to protect your helianthemum if you have a surprise late frost.

USDA Zone Info for Zone 1b

Here is the info for USDA Zone 1b.

Average Date of Last Frost (spring)June 15
Average Date of First Frost (fall)July 15
Lowest Expected Low-55°F
Highest Expected Low-50°F

This means that on a really cold year, the coldest it will get is -55°F. On most years you should be prepared to experience lows near -50°F.

Plants to Grow in Zone 1b

You may be interested in your other planting guides for Zone 1b.