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

The best time to plant helianthemum in Northbrook can be estimated 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 do well in moderate cold which tells us that you can get them planted earlier than more sensitive plants.

The earliest that you can plant helianthemum in Northbrook 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 fully mature. Starting your helianthemum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Northbrook 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 Northbrook is not always accurate the actual date of last frost is different every year. Since half of the time in Northbrook you get surprised by a frost after April 15 be ready to cover your helianthemum if you have one of those late frosts.

USDA Zone Info for Northbrook

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 Northbrook

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