One of the best tools that you have as gardeners to help us estimate 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.

You can estimate when to plant lithospermum in Flagstaff by referring to the USDA zone info.

Planting Calendar for Lithospermum

Frost tolerance for lithospermum:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Lithospermum do not do well in cold weather which means that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lithospermum in Flagstaff 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 lithospermum and expect a good harvest is probably August. Any later than that and your lithospermum may not have a chance to fully mature. Starting your lithospermum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Flagstaff the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Flagstaff is just an average the actual date of last frost changes from year to year. Half of the time in Flagstaff it frosts late in the year after April 15 so make sure that you are ready to protect your lithospermum if you have one of those late frosts.

USDA Zone Info for Flagstaff

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 Flagstaff

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