Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 determining when you can plant myosotis is to look at the USDA zone info for Portland.

Planting Calendar for Myosotis

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

Myosotis do well in moderate cold which tells us that you can get them planted earlier than other frost tender plants.

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

Last Frost Date

On average the last frost is on April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Portland and it can change quite a bit from year to year. Since half of the time in Portland it frosts late in the year after April 15 be ready to cover your myosotis in the event of one of those late frosts.

USDA Zone Info for Portland

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Portland

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