One of the first steps you take when you are figuring out your gardening schedule is find your 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.

By referring to the USDA zone info for Ottawa you should be able to estimate when it's a good idea to plant roses.

Planting Calendar for Roses

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

Roses are moderately cold tolerant which means that you can plant them a little bit earlier than more sensitive plants.

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

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Ottawa. In the coldest months of winter you can expect an average low temperature of -10°F.

Keep in mind that USDA zone info for Ottawa may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Ottawa you get surprised by a frost after April 15 so always be ready to cover your roses if you have one of those late frosts.

USDA Zone Info for Ottawa

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ottawa

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