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.

The first chance to plant trachelium in Portland can be determined by using the USDA zone info.

Planting Calendar for Trachelium

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

Since trachelium do not do well in cold weather it's necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant trachelium 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 trachelium and expect a good harvest is probably August. Any later than that and your trachelium may not have a chance to really do well. You can get started a couple of weeks earlier by starting your trachelium indoors.

Last Frost Date

In Portland the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in 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 last frost occurs after April 15 be ready to cover your trachelium in the event of a surprise late frost.

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.