The USDA Zone info is a great tool for gardeners to help us determine 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.

The USDA zone info for Campbell should be used to estimate when to plant helianthemum.

Planting Calendar for Helianthemum

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

Helianthemum are one of those plants that can tolerate a little bit of cold weather which tells us that you can start planting them earlier than other frost tender plants.

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

The last month that you can plant helianthemum and expect a good harvest is probably October. Any later than that and your helianthemum may not have a chance to really do well. Starting your helianthemum indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Campbell and it is different every year. Since half of the time in Campbell you get surprised by a frost after February 15 be ready to cover your helianthemum in the event of one of those late frosts.

USDA Zone Info for Campbell

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Campbell

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