One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to figure out when you can plant calliopsis by using the USDA zone info for Mill Creek.

Planting Calendar for Calliopsis

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

Calliopsis do not do well in cold weather which tells us that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant calliopsis in Mill Creek 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. Any later than that and your calliopsis may not have a chance to fully mature. If you are starting your calliopsis indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Mill Creek. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Mill Creek is just an average the actual date of last frost will vary from year to year. Half of the time in Mill Creek there is a last frost after March 15 so make sure that you are ready to cover your calliopsis if you have one of those late frosts.

USDA Zone Info for Mill Creek

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Mill Creek

You may be interested in your other planting guides for Mill Creek.