The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Lombard you can determine when to plant delphinium by checking out the USDA zone info.

Planting Calendar for Delphinium

Frost tolerance for delphinium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Delphinium do ok in a tiny bit of cold which means that you can plant them a bit earlier in the year than other frost tender plants.

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

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

Last Frost Date

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

Just be sure to remember that USDA zone info for Lombard is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Lombard you get surprised by a frost after April 15 so always be ready to protect your delphinium in the event of a late frost.

USDA Zone Info for Lombard

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 Lombard

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