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When to Plant Helianthemum in River Grove, IL

One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant helianthemum in River Grove can be estimated by reviewing 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 one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them earlier than other frost tender 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 River Grove 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 really do well. If you are starting your helianthemum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in River Grove. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for River Grove and it is different every year. Since half of the time in River Grove last frost occurs after April 15 be ready to cover your helianthemum if you have one of those late frosts.

USDA Zone Info for River Grove

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 River Grove

You may be interested in your other planting guides for River Grove.