One of the first steps you take when you are making a decision about 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.

A way of figuring out when it's the best time to plant rosemary is to look at the USDA zone info for Portland.

Planting Calendar for Rosemary

Frost tolerance for rosemary:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Rosemary can survive in pretty solid cold which tells us that you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant rosemary in Portland 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 rosemary and expect a good harvest is probably September. You probably don't want to wait any later than that or else your rosemary may not have a chance to really do well. If you are starting your rosemary indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Portland the average date of last frost happens on April 15. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Portland is just an average the actual date of last frost is different every year. Half of the time in Portland you get surprised by a frost after April 15 so be sure to be ready to cover your rosemary if you have a late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Portland

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