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.

You can determine when it's a good idea to plant catharanthus in Donna by referring to the USDA zone info.

Planting Calendar for Catharanthus

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

It's probably a bad idea to plant catharanthus until after the last frost because they are not cold tolerant.

The earliest that you can plant catharanthus in Donna is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant catharanthus and expect a good harvest is probably September. If you wait any later than that and your catharanthus may not have a chance to fully mature. 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 February 15 in Donna. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Donna is just an average the actual date of last frost changes from year to year. Since half of the time in Donna you get surprised by a frost after February 15 be ready to cover your catharanthus in the event of one of those late frosts.

USDA Zone Info for Donna

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Donna

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