Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant penstemon in Smithville should be determined 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 are moderately cold tolerant which tells us that you can plant them earlier than plants that are more sensitive to the cold.

The earliest that you can plant penstemon in Smithville 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. If you wait any later than that and your penstemon may not have a chance to grow to maturity. Starting your penstemon indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Smithville. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Smithville is just an average the actual date of last frost will vary from year to year. Since half of the time in Smithville you get surprised by a frost after April 15 be ready to protect your penstemon in the event of a late frost.

USDA Zone Info for Smithville

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Smithville

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