The USDA Zone info is a great tool for gardeners to help us figure out 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.

In Superior you can figure out when it's a good idea to plant erysimum by referring to the USDA zone info.

Planting Calendar for Erysimum

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

Since erysimum do well in moderate cold you can plant them a little earlier in the year than other plants that might not handle the cold.

The earliest that you can plant erysimum in Superior 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 erysimum and expect a good harvest is probably August. If you wait any later than that and your erysimum may not have a chance to grow to maturity. Starting your erysimum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Superior. In the coldest months of winter you should expect an average low temperature of -25°F.

It's important to remember that USDA zone info for Superior is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Superior there is a last frost after May 15 be ready to cover your erysimum if you have one of those late frosts.

USDA Zone Info for Superior

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 Superior

You may be interested in your other planting guides for Superior.