One of the first steps you take when you are figuring out 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.

By checking out the USDA zone info for Zone 5b you should be able to figure out when it's possible to plant catharanthus.

Planting Calendar for Catharanthus

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

You really shouldn't plant catharanthus until after the last frost has passed because they require warm weather.

The earliest that you can plant catharanthus in Zone 5b 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. If you wait any later than that and your catharanthus may not have a chance to grow to maturity. Starting your catharanthus indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Zone 5b. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Zone 5b and it is different every year. Half of the time in Zone 5b there is a last frost after April 15 so make sure that you are prepared to protect your catharanthus if you have a late frost.

USDA Zone Info for Zone 5b

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 Zone 5b

You may be interested in your other planting guides for Zone 5b.