One of the best tools that you have as gardeners to help us determine 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.

The first chance to plant four-o-clock flower in Prospect Heights should be estimated by referring to the USDA zone info.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After the last frost.

Four-o-clock flower are not cold tolerant which means that you have to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant four-o-clock flower in Prospect Heights 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 four-o-clock flower and expect a good harvest is probably August. If you wait any later than that and your four-o-clock flower may not have a chance to grow to maturity. Starting your four-o-clock flower indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Prospect Heights. It might get as low as -15°F during the coldest months of winter.

Keep in mind that USDA zone info for Prospect Heights is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Prospect Heights you get a frost after April 15 be ready to protect your four-o-clock flower if you have a late frost.

USDA Zone Info for Prospect Heights

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 Prospect Heights

You may be interested in your other planting guides for Prospect Heights.