One of the first steps you take when you are estimating 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.

The USDA zone info for Hillsboro can be reffered to in order to estimate when it's possible to plant calliopsis.

Planting Calendar for Calliopsis

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

Since calliopsis are not cold tolerant it is necessary to wait until after the last frost before you can plant them.

The earliest that you can plant calliopsis in Hillsboro 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 little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Hillsboro. You can expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Hillsboro is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Hillsboro last frost occurs after March 15 so just be sure to be ready to protect your calliopsis in the event of a late frost.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

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

Plants to Grow in Hillsboro

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