One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Helena can be used to estimate when you can plant strawflowers.

Planting Calendar for Strawflowers

Frost tolerance for strawflowers:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since strawflowers do ok in moderate cold you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant strawflowers in Helena 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 strawflowers and expect a good harvest is probably August. Any later than that and your strawflowers may not have a chance to fully mature. You can get started a few weeks earlier by starting your strawflowers indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Helena. It might get as low as 10°F during the coldest months of winter.

Keep in mind that USDA zone info for Helena is an average and the actual date of last frost is different every year. Half of the time in Helena there is a last frost after March 15 so make sure that you are ready to protect your strawflowers 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.