The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Roselle should be looked at to determine when to plant lobelia.

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 one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant lobelia in Roselle 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 fully mature. You can get started a couple of weeks earlier by starting your lobelia indoors.

Last Frost Date

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

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Roselle and it will vary from year to year. Half of the time in Roselle you get a frost after April 15 so be sure to be ready to cover your lobelia in the event of a late frost.

USDA Zone Info for Roselle

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 Roselle

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