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When to Plant Helianthemum in Mountlake Terrace, WA

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant helianthemum in Mountlake Terrace should be determined by using 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 are moderately cold tolerant which means that you can plant them earlier than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant helianthemum
Possibly ok, but a risky time to plant helianthemum
Probably not a good time to plant helianthemum

The earliest that you can plant helianthemum in Mountlake Terrace 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. If you are starting your helianthemum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Mountlake Terrace the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 15°F.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Mountlake Terrace and it will vary from year to year. Half of the time in Mountlake Terrace it frosts late in the year after March 15 so make sure that you are prepared to cover your helianthemum if you have a surprise late frost.

USDA Zone Info for Mountlake Terrace

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)March 15
Average Date of First Frost (fall)November 15
Lowest Expected Low15°F
Highest Expected Low20°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 20°F.

Plants to Grow in Mountlake Terrace

You may be interested in your other planting guides for Mountlake Terrace.