The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of figuring out when it's a good idea to plant helianthemum is to refer to the USDA zone info for Salem.

Planting Calendar for Helianthemum

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

Since helianthemum are moderately cold tolerant you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant helianthemum in Salem 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. You probably don't want to wait any later than that or else your helianthemum may not have a chance to fully mature. If you are starting your helianthemum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Salem. It might get as low as 15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Salem is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Salem there is a last frost after March 15 be ready to cover your helianthemum if you have one of those late frosts.

USDA Zone Info for Salem

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Salem

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