One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of getting a good idea when it's the best time to plant heliotrope is to use the USDA zone info for Gresham.

Planting Calendar for Heliotrope

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

Since heliotrope do not do well in cold weather it is necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant heliotrope in Gresham 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. 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 few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Gresham. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for Gresham is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Gresham you get surprised by a frost after March 15 be ready to protect your heliotrope if you have a surprise late frost.

USDA Zone Info for Gresham

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Gresham

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