The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant rudbeckia in Zone 4a can be estimated by looking at the USDA zone info.

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 get them planted earlier than plants that are more sensitive to the cold.

The earliest that you can plant rudbeckia in Zone 4a 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 rudbeckia and expect a good harvest is probably August. Any later than that and your rudbeckia may not have a chance to really do well. If you are starting your rudbeckia indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Zone 4a. It might get as low as -30°F during the coldest months of winter.

Keep in mind that USDA zone info for Zone 4a is just an average and the actual date of last frost is different every year. Half of the time in Zone 4a last frost occurs after May 15 so be sure to be ready to cover your rudbeckia in the event of a surprise late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

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

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.