One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when it's a good idea to plant lobelia is to examine the USDA zone info for Willowbrook.

Planting Calendar for Lobelia

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

Since lobelia are very cold tolerant you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant lobelia in Willowbrook 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 lobelia and expect a good harvest is probably September. Any later than that and your lobelia may not have a chance to really do well. Starting your lobelia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Willowbrook is an average and the actual date of last frost is different every year. Since half of the time in Willowbrook it frosts late in the year after April 15 be ready to protect your lobelia if you have a surprise late frost.

USDA Zone Info for Willowbrook

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 Willowbrook

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