One of the first steps you take when you are figuring out 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 can determine when it's the best time to plant common hollyhock in Hillsboro by referring to the USDA zone info.

Planting Calendar for Common hollyhock

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

You can plant common hollyhock a little earlier in the year because they do well in moderate cold.

The earliest that you can plant common hollyhock in Hillsboro 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 common hollyhock and expect a good harvest is probably September. If you wait any later than that and your common hollyhock may not have a chance to grow to maturity. You can get started a little bit earlier by starting your common hollyhock indoors.

Last Frost Date

In Hillsboro the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Hillsboro is just an average the actual date of last frost is different every year. Half of the time in Hillsboro last frost occurs after April 15 so make sure that you are prepared to cover your common hollyhock if you have a surprise late frost.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Hillsboro

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