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

A common way of making a decision about when it's possible to plant iresene is to look at the USDA zone info for Zone 4b.

Planting Calendar for Iresene

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

Since iresene do not do well in cold weather you must wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant iresene 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 iresene and expect a good harvest is probably August. If you wait any later than that and your iresene may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your iresene indoors.

Last Frost Date

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

Since the USDA zone info for Zone 4b is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 4b last frost occurs after May 15 be ready to cover your iresene in the event of a surprise 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.