One of the first steps you take when you are determining 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.

The USDA zone info for Helena should be read to estimate when to plant asparagus fern.

Planting Calendar for Asparagus Fern

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

Since asparagus fern do not do well in cold weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant asparagus fern in Helena 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 asparagus fern and expect a good harvest is probably August. You probably don't want to wait any later than that or else your asparagus fern may not have a chance to grow to maturity. Starting your asparagus fern indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Helena the average date of last frost happens on March 15. You can expect an average low temperature of 10°F in 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 March 15 so make sure that you are ready to protect your asparagus fern in the event of a surprise late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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