One of the first steps you take when you are estimating 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 USDA zone info for South Portland should be reviewed 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 all chance of frost has passed.

You can not plant catharanthus until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant catharanthus in South Portland 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. Any later than that and your catharanthus may not have a chance to fully mature. Starting your catharanthus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for South Portland is an average the actual date of last frost can change quite a bit from year to year. Half of the time in South Portland there is a last frost after April 15 so make sure that you are ready to cover your catharanthus in the event of one of those late frosts.

USDA Zone Info for South Portland

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 South Portland

You may be interested in your other planting guides for South Portland.