One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Whittier you should be able to estimate when you can plant penstemon.

Planting Calendar for Penstemon

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

Penstemon are moderately cold tolerant which tells us that you can plant them a little bit earlier than other plants that might not handle the cold.

The earliest that you can plant penstemon in Whittier 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. If you wait any later than that and your penstemon may not have a chance to really do well. You can get started a couple of weeks earlier by starting your penstemon indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in Whittier. It might get as low as 30°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Whittier and it changes from year to year. Since half of the time in Whittier it frosts late in the year after January 31 be ready to cover your penstemon if you have a late frost.

USDA Zone Info for Whittier

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Whittier

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