One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when you can plant heliotrope is to use the USDA zone info for Viroqua.

Planting Calendar for Heliotrope

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

Heliotrope are not cold tolerant which tells us that it's important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant heliotrope in Viroqua is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant heliotrope and expect a good harvest is probably August. Any later than that and your heliotrope may not have a chance to really do well. If you are starting your heliotrope indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on May 15 in Viroqua. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Viroqua may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Viroqua it frosts late in the year after May 15 be ready to cover your heliotrope in the event of a late frost.

USDA Zone Info for Viroqua

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

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

Plants to Grow in Viroqua

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