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

A way of estimating when you can plant delphinium is to use the USDA zone info for Wilmington.

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 moderate cold which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant delphinium in Wilmington 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 grow to maturity. If you are starting your delphinium indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Wilmington. In the coldest months of winter you should expect an average low temperature of 10°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Wilmington and it is different every year. Half of the time in Wilmington there is a last frost after March 15 so always be ready to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for Wilmington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Wilmington

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