One of the first steps you take when you are determining your gardening schedule is find your 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.

In Marshall you can estimate when it's possible to plant penstemon by looking at 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.

You can plant penstemon a little bit earlier in the year because they do well in moderate cold.

The earliest that you can plant penstemon in Marshall 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. You can get started a few weeks earlier by starting your penstemon indoors.

Last Frost Date

The average date of last frost is March 15 in Marshall. It might get as low as 15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Marshall and it will vary from year to year. Since half of the time in Marshall last frost occurs after March 15 be ready to cover your penstemon in the event of a surprise late frost.

USDA Zone Info for Marshall

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 Marshall

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