The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when to plant hollyhocks in Hillsboro by using the USDA zone info.

Planting Calendar for Hollyhocks

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

You can plant hollyhocks just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant hollyhocks 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 hollyhocks and expect a good harvest is probably September. You probably don't want to wait any later than that or else your hollyhocks may not have a chance to really do well. You can get started a few weeks earlier by starting your hollyhocks indoors.

Last Frost Date

In Hillsboro the average date of last frost happens on March 15. You should expect an average low temperature of 10°F in the coldest months of winter.

Keep in mind that USDA zone info for Hillsboro is not always accurate and the actual date of last frost is different every year. Half of the time in Hillsboro last frost occurs after March 15 so make sure that you are ready to cover your hollyhocks if you have 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.