One of the best tools that you have as gardeners to help us estimate 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.

A way of figuring out when it's the best time to plant mimulus is to refer to the USDA zone info for Hillsboro.

Planting Calendar for Mimulus

Frost tolerance for mimulus:	Not tolerant of frost.
When to plant:	After the last frost.

Since mimulus are not cold tolerant you need to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant mimulus 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 mimulus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your mimulus may not have a chance to fully mature. You can get started a little bit earlier by starting your mimulus 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.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Hillsboro and it changes from year to year. Since half of the time in Hillsboro it frosts late in the year after April 15 be ready to cover your mimulus 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.