One of the first steps you take when you are making a decision about 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.

A common way of estimating when you can plant lysimachia is to consult the USDA zone info for Havre.

Planting Calendar for Lysimachia

Frost tolerance for lysimachia:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant lysimachia a little bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant lysimachia in Havre 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 lysimachia and expect a good harvest is probably August. Any later than that and your lysimachia may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your lysimachia indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Havre. It might get as low as -30°F during the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Havre and it can change quite a bit from year to year. Since half of the time in Havre you get a frost after May 15 be ready to cover your lysimachia in the event of one of those late frosts.

USDA Zone Info for Havre

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Havre

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