One of the first steps you take when you are making a decision about your gardening schedule is find your 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.

A common way of estimating when it's a good idea to plant lithospermum is to consult the USDA zone info for Westminster.

Planting Calendar for Lithospermum

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

Since lithospermum require warm weather it is necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant lithospermum in Westminster 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. If you wait any later than that and your lithospermum may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your lithospermum indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Westminster. In the coldest months of winter you should expect an average low temperature of -15°F.

It's important to remember that USDA zone info for Westminster is just an average and the actual date of last frost is different every year. Since half of the time in Westminster it frosts late in the year after April 15 be ready to protect your lithospermum if you have one of those late frosts.

USDA Zone Info for Westminster

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 Westminster

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