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.

A way of determining when it's possible to plant helianthemum is to consult the USDA zone info for Prescott.

Planting Calendar for Helianthemum

Frost tolerance for helianthemum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant helianthemum a little earlier in the year because they are moderately cold tolerant.

The earliest that you can plant helianthemum in Prescott is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant helianthemum and expect a good harvest is probably September. Any later than that and your helianthemum may not have a chance to grow to maturity. If you are starting your helianthemum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Prescott. In the coldest months of winter you can expect an average low temperature of 10°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Prescott and it will vary from year to year. Since half of the time in Prescott it frosts late in the year after March 15 be ready to protect your helianthemum if you have one of those late frosts.

USDA Zone Info for Prescott

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 Prescott

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