One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Douglas it's a good idea to figure out when to plant catharanthus.

Planting Calendar for Catharanthus

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

Catharanthus do not do well in cold weather which tells us that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant catharanthus in Douglas 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 really do well. You can get started a couple of weeks earlier by starting your catharanthus indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Douglas. You can expect an average low temperature of 15°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Douglas and it is different every year. Half of the time in Douglas there is a last frost after March 15 so make sure that you are prepared to cover your catharanthus in the event of one of those late frosts.

USDA Zone Info for Douglas

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Douglas

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