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

In Durham you can estimate when it's a good idea to plant heliotrope by referring to the USDA zone info.

Planting Calendar for Heliotrope

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

Since heliotrope require warm weather you must wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant heliotrope in Durham is April. However, you really should wait until May 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 couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Durham. In the coldest months of winter you can expect an average low temperature of 5°F.

Since the USDA zone info for Durham is not always accurate the actual date of last frost is different every year. Half of the time in Durham you get surprised by a frost after April 15 so always be ready to protect your heliotrope in the event of one of those late frosts.

USDA Zone Info for Durham

Here is the info for USDA Zone 7b.

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

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

Plants to Grow in Durham

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