Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of estimating when to plant helianthemum is to look at the USDA zone info for Roy.

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 more sensitive plants.

The earliest that you can plant helianthemum in Roy 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. Starting your helianthemum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Roy. You can expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Roy is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Roy last frost occurs after April 15 be ready to cover your helianthemum in the event of a surprise late frost.

USDA Zone Info for Roy

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Roy

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