Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of making a decision about when it's a good idea to plant crossandra is to examine the USDA zone info for Helena.

Planting Calendar for Crossandra

Frost tolerance for crossandra:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since crossandra are not cold tolerant it's necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant crossandra in Helena 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 crossandra and expect a good harvest is probably August. You probably don't want to wait any later than that or else your crossandra may not have a chance to really do well. Starting your crossandra indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Helena the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Helena is not always accurate the actual date of last frost will vary from year to year. Half of the time in Helena last frost occurs after May 15 so make sure that you are ready to cover your crossandra if you have a surprise late frost.

USDA Zone Info for Helena

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 Helena

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