One of the first steps you take when you are estimating 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.

By checking out the USDA zone info for Portland it's possible to determine when to plant mimulus.

Planting Calendar for Mimulus

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

It's probably not a good idea to plant mimulus until after the last frost because they are not cold tolerant.

The earliest that you can plant mimulus in Portland 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. Any later than that and your mimulus may not have a chance to really do well. You can get started a little bit earlier by starting your mimulus indoors.

Last Frost Date

The average date of last frost is March 15 in Portland. You should expect an average low temperature of 15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Portland is an average and the actual date of last frost will vary from year to year. Since half of the time in Portland last frost occurs after March 15 be ready to cover your mimulus if you have one of those late frosts.

USDA Zone Info for Portland

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 Portland

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