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

In Ellensburg you can estimate when it's a good idea to plant helianthemum by referring to the USDA zone info.

Planting Calendar for Helianthemum

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

Helianthemum tend to make it in some cold which means that you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant helianthemum in Ellensburg 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. If you wait any later than that and your helianthemum may not have a chance to fully mature. You can get started a little bit earlier by starting your helianthemum indoors.

Last Frost Date

In Ellensburg the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ellensburg and it changes from year to year. Half of the time in Ellensburg it frosts late in the year after April 15 so be sure to be ready to protect your helianthemum in the event of a surprise late frost.

USDA Zone Info for Ellensburg

Here is the info for USDA Zone 6b.

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

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

Plants to Grow in Ellensburg

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