One of the first steps you take when you are estimating 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.

One way of figuring out when you can plant lithospermum is to use the USDA zone info for Dubuque.

Planting Calendar for Lithospermum

Frost tolerance for lithospermum:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You can not plant lithospermum until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant lithospermum in Dubuque 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 grow to maturity. You can get started a little bit earlier by starting your lithospermum indoors.

Last Frost Date

The average date of last frost is April 15 in Dubuque. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Dubuque is not always accurate the actual date of last frost is different every year. Half of the time in Dubuque last frost occurs after April 15 so make sure that you are prepared to protect your lithospermum if you have a late frost.

USDA Zone Info for Dubuque

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Dubuque

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