Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Longmont should be reffered to in order to figure out when it's a good idea to plant lithospermum.

Planting Calendar for Lithospermum

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

You can not plant lithospermum until after the last frost because they require warm weather.

The earliest that you can plant lithospermum in Longmont 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. You probably don't want to wait any later than that or else 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 Longmont 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.

Since the USDA zone info for Longmont is an average the actual date of last frost is different every year. Since half of the time in Longmont you get surprised by a frost after April 15 be ready to protect your lithospermum in the event of one of those late frosts.

USDA Zone Info for Longmont

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 Longmont

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