Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Casper should be looked at to estimate when to plant verbena.

Planting Calendar for Verbena

Frost tolerance for verbena:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant verbena a bit earlier in the year because they do ok in moderate cold.

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

The last month that you can plant verbena and expect a good harvest is probably August. Any later than that and your verbena may not have a chance to really do well. If you are starting your verbena indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Casper the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Remember that USDA zone info for Casper is just an average and the actual date of last frost changes from year to year. Since half of the time in Casper there is a last frost after April 15 be ready to cover your verbena in the event of a late frost.

USDA Zone Info for Casper

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Casper

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