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.

The best time to plant penstemon in Romulus can be determined by referring to 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 tend to make it in some cold which tells us that you can plant them just a bit earlier in the year than other frost tender plants.

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

Last Frost Date

The average date of last frost is April 15 in Romulus. It might get as low as -10°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Romulus is an average and the actual date of last frost changes from year to year. Half of the time in Romulus there is a last frost after April 15 so just be sure to be ready to protect your penstemon if you have one of those late frosts.

USDA Zone Info for Romulus

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Romulus

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