When to Plant Catharanthus in Lewistown, MT

One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant catharanthus in Lewistown can be estimated by referring to the USDA zone info.

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Planting Calendar for Catharanthus

Frost tolerance for catharanthus: Not tolerant of frost.
When to plant: After the last frost when the weather gets warmer.

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.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant catharanthus
Possibly ok, but a risky time to plant catharanthus
Probably not a good time to plant catharanthus

The earliest that you can plant catharanthus in Lewistown 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. You probably don't want to wait any later than that or else your catharanthus may not have a chance to really do well. If you are starting your catharanthus indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Lewistown the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Lewistown may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Lewistown last frost occurs after May 15 so be sure to be ready to cover your catharanthus in the event of a surprise late frost.

USDA Zone Info for Lewistown

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-30°F
Highest Expected Low-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Lewistown

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