When can I plant Helianthemum in Prospect Heights, IL

The USDA Zone info is a great tool for gardeners to help us figure out our gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for our area.

One way of estimating when to plant helianthemum is to refer to the USDA zone info for Prospect Heights.


Planting Calendar for Helianthemum

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

You can plant helianthemum a little bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

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 Prospect Heights 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. You probably don't want to wait any later than that or else your helianthemum may not have a chance to fully mature. If you are starting your helianthemum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Prospect Heights 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 Prospect Heights is an average our actual date of last frost will vary from year to year. Half of the time in Prospect Heights it frosts late in the year after April 15 so make sure that you are prepared to protect your helianthemum if we have a late frost.

USDA Zone Info for Prospect Heights

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 Prospect Heights

You may be interested in our other planting guides for Prospect Heights.