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

You should be able to determine when it's a good idea to plant lysimachia by using the USDA zone info for Ontario.

Planting Calendar for Lysimachia

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

Lysimachia do well in mild cold which tells us that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant lysimachia in Ontario 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 lysimachia and expect a good harvest is probably September. If you wait any later than that and your lysimachia may not have a chance to fully mature. Starting your lysimachia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ontario. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Ontario may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Ontario you get surprised by a frost after April 15 so always be ready to cover your lysimachia in the event of one of those late frosts.

USDA Zone Info for Ontario

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 Ontario

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