One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Gresham it's a good idea to figure out when to plant columbine.

Planting Calendar for Columbine

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

You can plant columbine a little bit earlier in the year because they are moderately cold tolerant.

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

Last Frost Date

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

Keep in mind that USDA zone info for Gresham is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Gresham there is a last frost after March 15 be ready to cover your columbine in the event of a late frost.

USDA Zone Info for Gresham

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 Gresham

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