Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant black eyed susans in Zone 4b should be determined by using the USDA zone info.

Planting Calendar for Black Eyed Susans

Frost tolerance for black eyed susans:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's not a good idea to plant black eyed susans until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant black eyed susans in Zone 4b 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 black eyed susans and expect a good harvest is probably August. If you wait any later than that and your black eyed susans may not have a chance to grow to maturity. You can get started a little bit earlier by starting your black eyed susans indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Zone 4b. It might get as low as -25°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Zone 4b and it is different every year. Since half of the time in Zone 4b last frost occurs after May 15 be ready to cover your black eyed susans if you have one of those late frosts.

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.