One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when it's possible to plant catharanthus in Castle Rock by looking at the USDA zone info.

Planting Calendar for Catharanthus

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

Catharanthus require warm weather which means that you have to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant catharanthus in Castle Rock 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 really do well. Starting your catharanthus indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Castle Rock. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Castle Rock is just an average the actual date of last frost is different every year. Half of the time in Castle Rock there is a last frost after April 15 so make sure that you are prepared to cover your catharanthus in the event of a surprise late frost.

USDA Zone Info for Castle Rock

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 Castle Rock

You may be interested in your other planting guides for Castle Rock.