The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to estimate when it's possible to plant trifolium by looking at the USDA zone info for Vienna.

Planting Calendar for Trifolium

Frost tolerance for trifolium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Trifolium are barely cold tolerant which means that you can get them planted just a bit earlier than other plants that might not handle the cold.

The earliest that you can plant trifolium in Vienna 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 trifolium and expect a good harvest is probably August. Any later than that and your trifolium may not have a chance to grow to maturity. You can get started a little bit earlier by starting your trifolium indoors.

Last Frost Date

On average the last frost is on April 15 in Vienna. You should expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Vienna is just an average the actual date of last frost is different every year. Since half of the time in Vienna you get a frost after April 15 be ready to protect your trifolium if you have one of those late frosts.

USDA Zone Info for Vienna

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Vienna

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