When to Plant Helianthemum in Cornelius, OR

One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. 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 Cornelius should be determined by looking at 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.

Since helianthemum are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than more sensitive plants.

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 Cornelius 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 really do well. You can get started a few weeks earlier by starting your helianthemum indoors.

Last Frost Date

In Cornelius the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Cornelius is just an average and the actual date of last frost changes from year to year. Since half of the time in Cornelius last frost occurs after March 15 be ready to protect your helianthemum in the event of one of those late frosts.

USDA Zone Info for Cornelius

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 Cornelius

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