Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Issaquah should be reffered to in order to determine 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 has passed.

Lithospermum do not do well in cold weather which tells us that you have to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant lithospermum in Issaquah 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 really do well. You can get started a few weeks earlier by starting your lithospermum indoors.

Last Frost Date

The average date of last frost is March 15 in Issaquah. In the coldest months of winter you should expect an average low temperature of 15°F.

Remember that USDA zone info for Issaquah is just an average and the actual date of last frost is different every year. Half of the time in Issaquah you get a frost after March 15 so make sure that you are prepared to cover your lithospermum in the event of one of those late frosts.

USDA Zone Info for Issaquah

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Issaquah

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