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

The USDA zone info for Powell should be looked at to determine when you can plant catharanthus.

Planting Calendar for Catharanthus

Frost tolerance for catharanthus:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant catharanthus until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant catharanthus in Powell is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant catharanthus and expect a good harvest is probably August. If you wait any later than that and your catharanthus may not have a chance to fully mature. If you are starting your catharanthus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Powell. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Powell is an average the actual date of last frost is different every year. Half of the time in Powell last frost occurs after May 15 so just be sure to be ready to cover your catharanthus in the event of a late frost.

USDA Zone Info for Powell

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Powell

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