Before planting it is a good idea to find your USDA Zone info to determine your garden 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 a good idea to estimate when it's the best time to plant heliotrope by using the USDA zone info for Phoenix.

Planting Calendar for Heliotrope

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

It's not a good idea to plant heliotrope until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant heliotrope in Phoenix 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 heliotrope and expect a good harvest is probably September. If you wait any later than that and your heliotrope may not have a chance to fully mature. If you are starting your heliotrope indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Phoenix the average date of last frost happens on February 15. You should expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Phoenix and it can change quite a bit from year to year. Half of the time in Phoenix last frost occurs after February 15 so always be ready to protect your heliotrope in the event of a surprise late frost.

USDA Zone Info for Phoenix

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Phoenix

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