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.

By reviewing the USDA zone info for Charleston you should be able to determine when it's the best time 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 do well in mild cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

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

The last month that you can plant rudbeckia and expect a good harvest is probably September. If you wait any later than that and your rudbeckia may not have a chance to grow to maturity. Starting your rudbeckia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Charleston. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Charleston is just an average the actual date of last frost is different every year. Half of the time in Charleston you get a frost after April 15 so make sure that you are prepared to protect your rudbeckia if you have a surprise late frost.

USDA Zone Info for Charleston

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Charleston

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