The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when to plant four-o-clock flower by referring to the USDA zone info for Hillsboro.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's a bad idea to plant four-o-clock flower until after the last frost has passed because they require warm weather.

The earliest that you can plant four-o-clock flower 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 four-o-clock flower and expect a good harvest is probably August. If you wait any later than that and your four-o-clock flower may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your four-o-clock flower indoors.

Last Frost Date

The average date of last frost is April 15 in Hillsboro. In the coldest months of winter you can expect an average low temperature of -10°F.

Always keep in mind that USDA zone info for Hillsboro is not always accurate and the actual date of last frost changes from year to year. Half of the time in Hillsboro last frost occurs after April 15 so just be sure to be ready to cover your four-o-clock flower if you have a 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.