One of the first steps you take when you are estimating your gardening schedule is find your 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.

The earliest that you can plant calliopsis in Aspen can be figured out by referring to the USDA zone info.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost.

Since calliopsis require warm weather it is necessary to wait until after the last frost has passed before you can plant them.

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

The last month that you can plant calliopsis and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calliopsis may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your calliopsis indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Aspen. It might get as low as -15°F during the coldest months of winter.

Always 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 Aspen and it can change quite a bit from year to year. Since half of the time in Aspen last frost occurs after April 15 be ready to protect your calliopsis in the event of a 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.