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

By referring to the USDA zone info for Signal Hill you will be able to estimate when to plant penstemon.

Planting Calendar for Penstemon

Frost tolerance for penstemon:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since penstemon are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant penstemon in Signal Hill is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant penstemon and expect a good harvest is probably October. Any later than that and your penstemon may not have a chance to grow to maturity. If you are starting your penstemon indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Signal Hill. You can expect an average low temperature of 35°F in the coldest months of winter.

Keep in mind that USDA zone info for Signal Hill may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Signal Hill you get a frost after January 31 be ready to protect your penstemon in the event of one of those late frosts.

USDA Zone Info for Signal Hill

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Signal Hill

You may be interested in your other planting guides for Signal Hill.