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.

In Portland you can figure out when it's the best time to plant balloon flower by checking out the USDA zone info.

Planting Calendar for Balloon Flower

Frost tolerance for balloon flower:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Balloon Flower do ok in moderate cold which means that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant balloon flower in Portland is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant balloon flower and expect a good harvest is probably August. Any later than that and your balloon flower may not have a chance to grow to maturity. If you are starting your balloon flower indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Portland is just an average the actual date of last frost changes from year to year. Since half of the time in Portland you get surprised by a frost after April 15 be ready to cover your balloon flower if you have 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.