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.

A way of figuring out when it's the best time to plant heliotrope is to look at the USDA zone info for Wausau.

Planting Calendar for Heliotrope

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

It's not a good idea to plant heliotrope until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant heliotrope in Wausau 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. If you wait any later than that and your heliotrope may not have a chance to fully mature. Starting your heliotrope indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Wausau. You can expect an average low temperature of -25°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Wausau is an average and the actual date of last frost will vary from year to year. Since half of the time in Wausau it frosts late in the year after May 15 be ready to cover your heliotrope if you have a surprise late frost.

USDA Zone Info for Wausau

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 Wausau

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