One of the first steps you take when you are getting a good idea 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.

You will be able to estimate when it's a good idea to plant catharanthus by referring to the USDA zone info for Rock Falls.

Planting Calendar for Catharanthus

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

It's probably not a good 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 Rock Falls is April. However, you really should wait until May 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 fully mature. You can get started a little bit earlier by starting your catharanthus indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Rock Falls. In the coldest months of winter you should expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Rock Falls is an average and the actual date of last frost will vary from year to year. Since half of the time in Rock Falls last frost occurs after April 15 be ready to protect your catharanthus if you have a late frost.

USDA Zone Info for Rock Falls

Here is the info for USDA Zone 5b.

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

Plants to Grow in Rock Falls

You may be interested in your other planting guides for Rock Falls.