The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 Zone 4b should be reviewed to determine when you can plant blue lace flowers.

Planting Calendar for Blue Lace Flowers

Frost tolerance for blue lace flowers:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant blue lace flowers slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant blue lace flowers in Zone 4b 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 blue lace flowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your blue lace flowers may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your blue lace flowers indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4b. You should expect an average low temperature of -25°F in the coldest months of winter.

Keep in mind that USDA zone info for Zone 4b is just an average and the actual date of last frost is different every year. Since half of the time in Zone 4b there is a last frost after May 15 be ready to protect your blue lace flowers if you have a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.