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.

In Castle Rock you can estimate when to plant erysimum by looking at the USDA zone info.

Planting Calendar for Erysimum

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

You can plant erysimum a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant erysimum in Castle Rock 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 erysimum and expect a good harvest is probably September. If you wait any later than that and your erysimum may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your erysimum indoors.

Last Frost Date

In Castle Rock the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Castle Rock is just an average the actual date of last frost is different every year. Half of the time in Castle Rock there is a last frost after April 15 so be sure to be ready to protect your erysimum if you have a surprise late frost.

USDA Zone Info for Castle Rock

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Castle Rock

You may be interested in your other planting guides for Castle Rock.