One of the best tools that you have as gardeners to help us estimate 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.

One way of figuring out when it's possible to plant helianthemum is to refer to the USDA zone info for Rosenberg.

Planting Calendar for Helianthemum

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

Since helianthemum do well in moderate cold you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant helianthemum in Rosenberg 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. If you wait 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 couple of weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Rosenberg. It might get as low as 20°F during the coldest months of winter.

It's important to 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 Rosenberg and it will vary from year to year. Half of the time in Rosenberg you get surprised by a frost after February 15 so make sure that you are prepared to protect your helianthemum if you have one of those late frosts.

USDA Zone Info for Rosenberg

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Rosenberg

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