One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to estimate when it's the best time to plant tritoma by using the USDA zone info for Colville.

Planting Calendar for Tritoma

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

Tritoma do well in a bit of cold which tells us that you can plant them much earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

The average date of last frost is April 15 in Colville. You should expect an average low temperature of -10°F in the coldest months of winter.

Keep in mind that USDA zone info for Colville is an average and the actual date of last frost is different every year. Half of the time in Colville you get surprised by a frost after April 15 so always be ready to protect your tritoma in the event of a surprise late frost.

USDA Zone Info for Colville

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Colville

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