Before planting it is a good idea to find your USDA Zone info to estimate your garden 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 can be looked at to figure out when to plant aubrieta.

Planting Calendar for Aubrieta

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

You can plant aubrieta a little bit earlier in the year because they do well in moderate cold.

The earliest that you can plant aubrieta in Zone 4b is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant aubrieta and expect a good harvest is probably August. Any later than that and your aubrieta may not have a chance to fully mature. You can get started a few weeks earlier by starting your aubrieta indoors.

Last Frost Date

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

Just be sure to remember that USDA zone info for Zone 4b may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Zone 4b you get surprised by a frost after May 15 so just be sure to be ready to protect your aubrieta 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.