When to Plant Hardy Hibiscus in Ottawa, IL

One of the first steps you take when you are getting a good idea 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 using the USDA zone info for Ottawa you should be able to determine when you can plant hardy hibiscus.

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Planting Calendar for Hardy Hibiscus

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

You can plant hardy hibiscus quite a bit earlier in the year because they are very cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant hardy hibiscus
Possibly ok, but a risky time to plant hardy hibiscus
Probably not a good time to plant hardy hibiscus

The earliest that you can plant hardy hibiscus 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 hardy hibiscus and expect a good harvest is probably September. You probably don't want to wait any later than that or else your hardy hibiscus may not have a chance to grow to maturity. If you are starting your hardy hibiscus indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Ottawa the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ottawa and it is different every year. Since half of the time in Ottawa it frosts late in the year after April 15 be ready to protect your hardy hibiscus if you have a surprise late frost.

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.