One of the first steps you take when you are getting a good idea 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.

You can determine when to plant helianthemum in Madison 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 can survive in a little bit of cold which tells us that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant helianthemum in Madison is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant helianthemum and expect a good harvest is probably August. If you wait any later than that and 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 little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Madison. You should expect an average low temperature of -25°F in the coldest months of winter.

Remember that USDA zone info for Madison is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Madison you get surprised by a frost after May 15 be ready to protect your helianthemum if you have one of those late frosts.

USDA Zone Info for Madison

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Madison

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