Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to figure out when it's possible to plant lobelia by referring to the USDA zone info for Rock Springs.

Planting Calendar for Lobelia

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

Lobelia tend to make it in cold weather which tells us that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant lobelia in Rock Springs 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. If you wait any later than that and your lobelia may not have a chance to fully mature. You can get started a few weeks earlier by starting your lobelia indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Rock Springs. You should expect an average low temperature of -20°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Rock Springs and it will vary from year to year. Since half of the time in Rock Springs you get a frost after April 15 be ready to protect your lobelia in the event of a surprise late frost.

USDA Zone Info for Rock Springs

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Rock Springs

You may be interested in your other planting guides for Rock Springs.