One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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.

By checking out the USDA zone info for Oregon City it's a good idea to figure out when it's a good idea to plant common hollyhock.

Planting Calendar for Common hollyhock

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

Common hollyhock do well in moderate cold which tells us that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant common hollyhock in Oregon City 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 Oregon City the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Oregon City is just an average the actual date of last frost changes from year to year. Half of the time in Oregon City you get a frost after March 15 so make sure that you are prepared to cover your common hollyhock in the event of a late frost.

USDA Zone Info for Oregon City

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 Oregon City

You may be interested in your other planting guides for Oregon City.