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

The USDA zone info for Zone 1a should be reviewed to determine when it's a good idea to plant iberis.

Planting Calendar for Iberis

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

Iberis do ok in a little bit of cold which means that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant iberis 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 iberis and expect a good harvest is probably July. If you wait any later than that and your iberis may not have a chance to grow to maturity. Starting your iberis 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. In the coldest months of winter you can expect an average low temperature of -60°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 1a and it will vary from year to year. Since half of the time in Zone 1a there is a last frost after June 15 be ready to protect your iberis in the event of a surprise 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 your other planting guides for Zone 1a.