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.

In Oakland you can determine when it's the best time to plant penstemon by using the USDA zone info.

Planting Calendar for Penstemon

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

Penstemon do well in moderate cold which tells us that you can plant them a little earlier in the year than more sensitive plants.

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

The last month that you can plant penstemon and expect a good harvest is probably September. You probably don't want to wait any later than that or else your penstemon may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your penstemon indoors.

Last Frost Date

The average date of last frost is April 15 in Oakland. You should expect an average low temperature of -5°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Oakland and it is different every year. Half of the time in Oakland you get surprised by a frost after April 15 so always be ready to protect your penstemon if you have a late frost.

USDA Zone Info for Oakland

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Oakland

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