The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to determine when it's the best time to plant catharanthus by reviewing the USDA zone info for Zone 1b.

Planting Calendar for Catharanthus

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

Since catharanthus do not do well in cold weather it is necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant catharanthus in Zone 1b is June. However, you really should wait until July if you don't want to take any chances.

The last month that you can plant catharanthus and expect a good harvest is probably July. Any later than that and 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 few weeks earlier.

Last Frost Date

The average date of last frost is June 15 in Zone 1b. You can expect an average low temperature of -55°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 1b is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 1b it frosts late in the year after June 15 be ready to protect your catharanthus in the event of a late frost.

USDA Zone Info for Zone 1b

Here is the info for USDA Zone 1b.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-55°F
Highest Expected Low	-50°F

This means that on a really cold year, the coldest it will get is -55°F. On most years you should be prepared to experience lows near -50°F.

Plants to Grow in Zone 1b

You may be interested in your other planting guides for Zone 1b.