One of the first steps you take when you are making a decision about 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 reviewing the USDA zone info for Thornton you should be able to figure out when to plant hibiscus.

Planting Calendar for Hibiscus

Frost tolerance for hibiscus:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since hibiscus are not cold tolerant it's important to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant hibiscus in Thornton is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant hibiscus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your hibiscus may not have a chance to really do well. Starting your hibiscus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Thornton. It might get as low as -15°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 Thornton and it can change quite a bit from year to year. Half of the time in Thornton last frost occurs after April 15 so make sure that you are ready to cover your hibiscus if you have a surprise late frost.

USDA Zone Info for Thornton

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 Thornton

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