One of the first steps you take when you are estimating your gardening schedule is find your 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.

The USDA zone info for Charleston should be used to figure out when it's a good idea to plant rudbeckia.

Planting Calendar for Rudbeckia

Frost tolerance for rudbeckia:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Rudbeckia are one of those plants that can tolerate a little bit of cold weather which tells us that you can start planting them earlier than other plants that might not handle the cold.

The earliest that you can plant rudbeckia in Charleston is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant rudbeckia and expect a good harvest is probably October. If you wait any later than that and your rudbeckia may not have a chance to fully mature. If you are starting your rudbeckia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Charleston the average date of last frost happens on February 15. In the coldest months of winter you should expect an average low temperature of 20°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Charleston and it is different every year. Since half of the time in Charleston there is a last frost after February 15 be ready to protect your rudbeckia in the event of one of those late frosts.

USDA Zone Info for Charleston

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Charleston

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