One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. 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 figure out when it's possible to plant creeping phlox by referring to the USDA zone info for Ottawa.

Planting Calendar for Creeping Phlox

Frost tolerance for creeping phlox:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Creeping Phlox are very cold tolerant which tells us that you can start planting them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant creeping phlox in Ottawa 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 creeping phlox and expect a good harvest is probably September. Any later than that and your creeping phlox may not have a chance to really do well. You can get started a couple of weeks earlier by starting your creeping phlox indoors.

Last Frost Date

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

Keep in mind that USDA zone info for Ottawa is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Ottawa last frost occurs after April 15 so make sure that you are prepared to protect your creeping phlox if you have one of those late frosts.

USDA Zone Info for Ottawa

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 Ottawa

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