Before planting it is a good idea to find your USDA Zone info to figure out your garden 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 Aspen should be looked at to figure out when to plant erysimum.

Planting Calendar for Erysimum

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

Erysimum are one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant erysimum in Aspen is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant erysimum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your erysimum may not have a chance to fully mature. Starting your erysimum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Aspen the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Aspen is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Aspen you get surprised by a frost after April 15 be ready to protect your erysimum in the event of a surprise late frost.

USDA Zone Info for Aspen

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Aspen

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